Abstract: Memory devices are provided. The memory device includes a substrate. A dielectric layer is disposed on the substrate and a plurality of resistive memory cells is disposed on the dielectric layer. Each resistive memory cell includes a via disposed in a first opening of the dielectric layer. A conductive layer is disposed on the via. The memory device further includes a capacitor structure including a bottom electrode, a variable resistance layer disposed on the bottom electrode and a top electrode disposed on the variable resistance layer, wherein the bottom electrode is disposed on the conductive layer.

Abstract: According to one embodiment, a logical operation circuit includes a magnetic tunnel junction (MTJ) element and driver. The MTJ element includes a first magnetic layer, a second magnetic layer, and an intermediate layer between the first and second magnetic layers. An orientation of magnetization of the second magnetic layer flips by a first current which flows through the MTJ element in a first state from the second magnetic layer to the first magnetic layer. The driver is coupled to the first magnetic layer without a magnetic layer interposed and coupled to the second magnetic layer, and passes a second current through the MTJ element in the first state from the second magnetic layer to the first magnetic layer. A magnitude of the second current is larger than 1.5 times a magnitude of the first current.

Abstract: A logical operation array of a resistive random access memory includes at least one logical operation unit; each logical operation unit includes multiple resistive random access memories, multiple field effect transistor switches and a voltage converter.

Abstract: Methods of fabricating MRAM devices are provided along with a processing apparatus for fabricating the MRAM devices. The methods may include forming a ferromagnetic layer, cooling the ferromagnetic layer to a temperature within a range of between about 50° K to about 300° K, forming and oxidizing one or more Mg layers on the cooled ferromagnetic layer to form an MgO structure, forming a free layer on the MgO structure, and forming a capping layer on the free layer.

Abstract: Method for writing and reading a plurality of data bits to a magnetic random access memory (MRAM) cell including a magnetic tunnel junction including a reference magnetic layer having a reference magnetization, a tunnel barrier layer, and a SAF storage magnetic layer including a first and second storage magnetization being coupled antiparallel through a storage coupling layer and freely orientable at a high temperature threshold. The method includes: heating the magnetic tunnel junction to the high temperature threshold; and applying a write magnetic field to orient the first and second storage magnetization; wherein the high temperature threshold includes one of a first or third high temperature threshold such as to orient the first storage magnetization respectively antiparallel or parallel to the second storage magnetization; or a second high temperature threshold such as to orient the first storage magnetization with an angle below 180° with respect to the second storage magnetization.

Abstract: A semiconductor memory device includes a memory cell array including a plurality of memory cells, a read and write circuit temporarily storing program data to be programmed into the memory cell array during a program operation, and reading data stored in the memory cell array and temporarily storing read data during a read operation, and a control logic detecting an error in the program operation by comparing the program data with the read data.

Abstract: A circuit and method for adaptive trimming of the reference signal for sensing data during a read operation of magnetic memory cells to improve read margin for the magnetic memory cells. The circuit has a trim one-time programmable memory array programmed with offset trim data applied to magnetic memory array sense amplifiers. Sense amplifier trimming circuits receive and decode the trim data to determine offset trim signal magnitude to adjust the reference signal to improve the read margin. The method sets the offset trim level to each increment of the offset trim level. Data is written and read to the magnetic memory array, the number of errors in the array is accumulated for each setting of the offset trim level. The error levels are compared and the appropriate trim level is programmed to the trim memory cells such that a read margin of the sense amplifier is improved.

Abstract: A write apparatus and a magnetic memory, where the write apparatus includes a first drive port, a second drive port, a first information storage area, a second information storage area, and an information buffer. A first area locates between the first information storage area and the information buffer. A second area locates between the second information storage area and the information buffer. The first information storage area, the second information storage area, and the information buffer are made of a first magnetic material. The first area and the second area are made of a second magnetic material. Magnetic energy of the first magnetic material is higher than magnetic energy of the second magnetic material. The write apparatus can ensure write stability of the magnetic memory.

Abstract: Magnetic random-access memory (RAM) cells and arrays are described based on magnetoresistive thin-film structures.

Abstract: An arbitration system and method is disclosed. The apparatus includes first and second memory devices, and a resistor coupled in common to the first and second memory devices, the first memory device including a first calibration circuit configured to perform, when activated, a first calibration operation based on the resistor and a first arbiter configured to activate the first calibration circuit responsive, at least in part, to an assertion of a first command or keep the first calibration circuit inactive irrespective of the assertion of the first command.

Abstract: A method of applying a write current to a magnetic tunnel junction device minimizes sub-threshold leakage. NMOS- and PMOS-follower circuits are used in applying the write current, and bias signals for the follower circuits are isolated from global bias signals before the write current is applied.

Abstract: In one embodiment, a system includes a sensor, the sensor having a free layer, a ferromagnetic spin sink layer spaced from the free layer, the spin sink layer being operative to reduce a spin-induced damping in the free layer during operation of the sensor, and a nonmagnetic spacer layer positioned between the free layer and the spin sink layer, the spacer layer having a long spin-diffusion length.

Abstract: Row electrode drivers and column electrode drivers for a memory device are distributed within a footprint share by a memory cell array.

Abstract: A reference circuit for a magnetic random access memory (MRAM) is provided. The reference circuit includes a plurality of device strings coupled in parallel. Each of the device strings includes a plurality of magnetic tunnel junction (MTJ) devices coupled in serial. A quantity of MTJ devices of each of the device strings is equal to a quantity of device strings. An equivalent resistance of the MTJ devices is equal to the resistance of one of the MTJ devices.

Abstract: A semiconductor device includes a first magnetic tunnel junction (MTJ) device, a second MTJ device, and a top electrode. The first MTJ device includes a barrier layer. The second MTJ device includes the barrier layer. The top electrode is coupled to the first MTJ device and the second MTJ device.

Abstract: A semiconductor memory cell and arrays of memory cells are provided In at least one embodiment, a memory cell includes a substrate having a top surface, the substrate having a first conductivity type selected from a p-type conductivity type and an n-type conductivity type; a first region having a second conductivity type selected from the p-type and n-type conductivity types, the second conductivity type being different from the first conductivity type, the first region being formed in the substrate and exposed at the top surface; a second region having the second conductivity type, the second region being formed in the substrate, spaced apart from the first region and exposed at the top surface; a buried layer in the substrate below the first and second regions, spaced apart from the first and second regions and having the second conductivity type; a body region formed between the first and second regions and the buried layer, the body region having the first conductivity type; a gate positioned between the

Abstract: According to one embodiment, a memory system includes a semiconductor memory and a memory controller. The memory controller writes a first data group in the semiconductor memory and then reads the first data group from the semiconductor memory. The memory controller counts a number of first data and a number of second data based on a comparison of a second data group with a third data group. The memory controller changes a first charge threshold based on the number of first data and the number of second data. The second data group is the first data group at the time of writing to the semiconductor memory. The third data group is the first data group read from the semiconductor memory. The first data is data changed from a first code to a second code. The second data is data changed from the second code to the first code.

Abstract: Memory cells are disclosed. Magnetic regions within the memory cells include an alternating structure of magnetic sub-regions and coupler sub-regions. The coupler material of the coupler sub-regions antiferromagnetically couples neighboring magnetic sub-regions and effects or encourages a vertical magnetic orientation exhibited by the neighboring magnetic sub-regions. Neighboring magnetic sub-regions, spaced from one another by a coupler sub-region, exhibit oppositely directed magnetic orientations. The magnetic and coupler sub-regions may each be of a thickness tailored to form the magnetic region in a compact structure. Interference between magnetic dipole fields emitted from the magnetic region on switching of a free region in the memory cell may be reduced or eliminated. Also disclosed are semiconductor device structures, spin torque transfer magnetic random access memory (STT-MRAM) systems, and methods of fabrication.

Abstract: A storage device according to an embodiment includes: first and second magnetic elements each including: a reference layer connected to a third terminal; a first magnetic layer including first through third magnetic regions; a nonmagnetic layer; a second magnetic layer connected to a first terminal and the first magnetic region; and a third magnetic layer connected to a second terminal and the third magnetic region; a first inverter including a p-channel first transistor, an n-channel second transistor, a first input terminal connected to the second terminal of the second magnetic element, and a first output terminal connected to the first terminal of the first magnetic element; and a second inverter including a p-channel third transistor, an n-channel fourth transistor, a second input terminal connected to the second terminal of the first magnetic element, and a second output terminal connected to the first terminal of the second magnetic element.

Abstract: The memory controller comprises a storage unit in which the Registered-System-Max-NOE is registered per logical area and a processor which registers, in the storage unit, the System-Max-NOE (the maximum value of multiple erasures respectively corresponded to multiple physical areas) at the time when allocating a spare physical area in one of the logical areas as the Registered-System-Max-NOE to be associated with the allocation destination logical area. The processor performs a wear leveling processing based on the Registered-System-Max-NOE per logical area.

Abstract: A method of erasing, during an erase operation, a non-volatile memory (NVM) cell of a memory device is disclosed. The erasing includes applying a first HV signal (VPOS) to a common source line (CSL). The CSL is shared among NVM cells of a sector of NVM cells. The first HV signal is above a highest voltage of a power supply. The erasing also includes applying the first HV signal to a local bit line (BL).

Abstract: Embodiments herein describe a SRAM that selectively flips received chunks of data from a high power state to a low power state before storing the chunks of data. The SRAM generates a flip bit for each of the data chunks stored in memory. The state of the flip bit varies depending on whether the corresponding data chunk was flipped before being stored in the SRAM. In one embodiment, the SRAM flips the bits in a data chunk before storing the bits only if all the bits are in the high power state. If so, the SRAM sets the flip bit for the data chunk to a first state and changes all the bits to the low power state before storing the data chunk. If not, the SRAM sets the flip bit to a second state and stores the data chunk without changing the states of the bits.

Abstract: A method may include applying a first current through the memory element and a first selection component. The memory element and the first selection component may be located along a memory line. The method may also include measuring a first potential difference across the memory line. The method may further include applying a second current through a second selection component, wherein the second selection component is located along a dummy line, and measuring a second potential difference across the dummy line. The method may additionally include determining the resistance of the memory element based on the first potential difference and the second potential difference. The first selection component may be activated and the second selection component may be deactivated to apply the first current. The first selection component may be deactivated and the second selection component may be activated to apply the second current.

Abstract: An integrated circuit according to an embodiment includes: a plurality of first wiring lines; a plurality of second wiring lines intersecting with the plurality of first wiring lines; a plurality of resistive change memory elements provided in cross regions of the plurality of first and second wiring lines, each of which includes a first electrode connected to a corresponding first wiring line, a second electrode connected to a corresponding second wiring line, and a resistive change layer provided between the first and second electrodes, and in each of which a resistive state between the first electrode and the second electrode can be programmed from one of a first resistive state and a second resistive state, which has a larger resistance value than the first resistive state, to the other; and a driver driving the plurality of first and second wiring lines.

Abstract: Systems and methods relate to operations on a magnetoresistive random access memory (MRAM) bit cell using a circuit configured in multiple phases. In a sensing circuit phase, the circuit configured to determine a first differential voltage between a data voltage across the bit cell and a reference voltage. In a pre-amplifying phase, the circuit is configured to pre-amplify the first differential voltage to generate a pre-amplified differential voltage, which does not have offset voltages that may arise due to process variations. In a sense amplifier phase, the circuit is configured to amplify the pre-amplified differential voltage in a latch. Generation of the pre-amplified differential voltage cancels offset voltages which may arise in the latch. In a write phase, the circuit is further configured to write a write data value to the MRAM bit cell.

Abstract: A method of programming an MTJ includes selecting the MTJ and an access transistor coupled thereto. The gate of the selected access transistor is coupled to a selected word line (WL), which is raised to a first voltage, Vdd, and is then allowed to float. The first voltage and a second voltage, Vx, are respectively applied to a selected bit line (BL) coupled to the selected MTJ and a selected source line (SL) coupled to the selected access transistor, thereby driving a switching current through the selected MTJ from the selected BL to SL. Alternatively, the switching current may be reversed by applying 0 V and Vdd to the selected BL and SL, respectively. Moreover, the second voltage is applied to other BLs not coupled to the selected MTJ and the first voltage is applied to other SLs not coupled to the selected access transistor, thereby boosting the voltage of the floating WL to above the first voltage.

Abstract: A configurable ME MTJ XOR/XNOR gate includes an insulator separating a top and bottom FM layer, a top ME layer with a first boundary magnetism at an interface of the top ME layer and the top FM layer, a bottom ME layer with a second boundary magnetism at an interface of the bottom ME layer and the bottom FM layer, and a top electrode coupled to the top ME layer and a bottom electrode coupled to the bottom ME layer. A voltage between the top electrode and FM layer is a first input, a voltage between the bottom electrode and FM layer is a second input, and a resistance between the top and bottom FM layer is indicative of the XOR or the XNOR of the inputs. The configurable ME MTJ XOR/XNOR gate has reduced energy consumption, smaller area, faster switching times, is non-volatile, and is configurable.

Abstract: A semiconductor memory device includes a shorted variable resistor element in a memory cell. The semiconductor memory device includes main cells and reference cells each including a cell transistor and a variable resistor element. The variable resistor element of the reference cell is shorted by applying a breakdown voltage of a magnetic tunnel junction (MTJ) element, connection in parallel to a conductive via element, connection to a reference bit line at a node between the cell transistor and the variable resistor element, or replacement of the variable resistor element with the conductive via element. A sense amplifier increases a sensing margin of the main cell by detecting and amplifying a current flowing in a bit line of the main cell and a current flowing in the reference bit line to which a reference resistor is connected.

Abstract: A semiconductor memory device may include a pillar, a gate and at least one ferroelectric layer. The pillar may include a source, a drain and a channel region. The drain may be arranged over the source. The channel region may be arranged between the source and the drain. The gate may be formed on an outer surface of the pillar. The ferroelectric layer may be interposed between the pillar and the gate.

Abstract: A sensing method for a memory is provided. The memory includes: a memory cell; a reference circuit generating a reference voltage and a clamp voltage; and a current supplying circuit receiving the clamp voltage to develop a cell current passing through the memory cell to form a cell voltage, wherein the cell voltage is used for incorporating with the reference voltage to determine the information stored in the memory.

Abstract: In a tunnel junction element having a ferromagnetic free layer, an insulating layer and a ferromagnetic fixed layer, in order to reduce the current necessary for spin-transfer magnetization reversal operation in the tunnel junction element, the ferromagnetic free layer comprises first and second ferromagnetic layers, a nonmagnetic metal layer is provided between these ferromagnetic layers, the nonmagnetic metal layer is such that magnetic coupling is preserved between the first and second ferromagnetic layers, also such that there is no influence on the crystal growth of the first and second ferromagnetic layers, the first ferromagnetic layer and the second ferromagnetic layer are placed such that the first ferromagnetic layer is in contact with the insulating layer, and the second ferromagnetic layer has a smaller magnetization than the first ferromagnetic layer.

Abstract: A device is disclosed that includes a driver, a sinker, a memory column, a reference column, a reference resistor and a sensing unit. At least one of the driver and the sinker has a trimmable resistance. For write operation, one of resistive memory cells is conducted based on a row location in the memory column thereof, the driver provides a write current flowing therethrough and the trimmable resistance is trimmed based on the row location. For read operation, the sensing unit senses a read current of the memory column and a reference current of the reference column and the reference resistor when one of the resistive memory cells and a positionally corresponding one of the reference bit cells are conducted.

Abstract: The present disclosure concerns a magnetic random access memory cell containing a magnetic tunnel junction formed from an insulating layer comprised between a sense layer and a storage layer. The present disclosure also concerns a method for writing and reading the memory cell comprising, during a write operation, switching a magnetization direction of said storage layer to write data to said storage layer and, during a read operation, aligning magnetization direction of said sense layer in a first aligned direction and comparing said write data with said first aligned direction by measuring a first resistance value of said magnetic tunnel junction. The disclosed memory cell and method allow for performing the write and read operations with low power consumption and an increased speed.

Abstract: A method for forming a resistive memory device includes providing a substrate comprising a first metal material, forming a conductive silicon-bearing layer on top of the first metal material, wherein the conductive silicon-bearing layer comprises an upper region and a lower region, and wherein the lower region is adjacent to the first metal material, forming an amorphous layer from the upper region of the conductive silicon-bearing layer, and disposing an active metal material above the amorphous layer.

Abstract: A layered stack includes a first layer having a first spin polarization and a first magnetic moment, as well as a second layer (in contact with the first layer) having a second spin polarization a second magnetic moment. The first and second spin polarizations have the same orientation, but the first and second magnetic moments have orientations that partially cancel each other, thereby recommending the layered stack for applications in magnetic tunnel junctions, for example.

Abstract: An arbitration system and method is disclosed. The apparatus includes first and second memory devices, and a resistor coupled in common to the first and second memory devices, the first memory device including a first calibration circuit configured to perform, when activated, a first calibration operation based on the resistor and a first arbiter configured to activate the first calibration circuit responsive, at least in part, to an assertion of a first command or keep the first calibration circuit inactive irrespective of the assertion of the first command.

Abstract: A memory includes first signal-lines, second signal-lines and resistance-change memory cells. First and second drivers can supply power to the first and second signal-lines, respectively. The second driver increases a voltage of a selected second signal-line in a write-loop higher than that in a previous write-loop. The write-loop includes a write operation and a verify operation. A voltage increase width of the selected second signal-line at a time of transition from a first write-loop to a second write-loop is larger than a voltage increase width of the selected second signal-line at a time of transition from the second write-loop to a third write-loop. A voltage increase width of the selected second signal-line at a time of transition from the second write-loop to the third write-loop is smaller than a voltage increase width of the selected second signal-line at a time of transition from the third write-loop to a forth write-loop.

Abstract: A multi-port memory cell including: first and second magnetoresistive elements, each of which is programmable so as to adopt at least two resistive states, in which: the first magnetoresistive element is coupled with a first output line and is programmable by the direction of a current which is passed through same; and the second magnetoresistive element is coupled with a second output line and is arranged so as to be magnetically coupled with the first magnetoresistive element, the second magnetoresistive element being programmable by a magnetic field generated by the first magnetoresistive element.

Abstract: An embodiment of the present invention includes a mass storage device with a storage media that includes magnetic random access memory (MRAM) devices with a NAND flash interface and NAND flash memory devices that are coupled to the MRAM devices. The storage media is partitioned into a hybrid reserved area made of a combination of MRAM array and NAND array and a hybrid user area made of a combination of MRAM array and NAND array. The mass storage device further includes a controller with a host interface and a flash interface coupled to the MRAM and NAND flash memory devices through the flash interface.

Abstract: An SSD controller dynamically adjusts read thresholds in an NVM to reduce errors due to device threshold voltage distribution shifts, thus improving performance, reliability, and/or cost of a storage sub-system, such as an SSD. A retention drift clock uses one or more reference pages (or ECC units or blocks) on one or more NVM die as read threshold over time/temperature references, and uses a function of those values as a measure of drift (over time/temperature). At some initial time, the one or more reference pages are programmed and an initial read threshold is measured for each of the one or more reference pages. In some embodiments, read threshold values are averaged among one or more of: all references pages on the same die; and all reference pages in the same one or more die in an I/O device.

Abstract: According to one embodiment, a reconfigurable circuit includes circuit blocks arranged with a matrix of A rows and B columns. Each of the circuit blocks includes M row conductive lines, N column conductive lines crossing the row conductive lines, output inverters each having input and output terminals, the input terminal of each output inverter connected to corresponding one of the row conductive lines, input inverters each having input and output terminals, the output terminal of each input inverter connected to corresponding one of the column conductive lines, and resistance change elements between the row conductive lines and the column conductive lines, each of the resistance change elements including a first terminal and a second terminal, the first terminal being connected to corresponding one of the row conductive lines, the second terminal being connected to corresponding one of the column conductive lines.

Abstract: Methods and apparatus relating to spin-orbit-torque magnetoresistive random access memory with voltage-controlled anisotropy are disclosed. In an example, disclosed is a three-terminal magnetic tunnel junction (MTJ) storage element that is programmed via a combination of voltage-controlled magnetic anisotropy (VCMA) and spin-orbit torque (SOT) techniques. Also disclosed is a memory controller configured to program the three-terminal MTJ storage element via VCMA and SOT techniques. The disclosed devices improve efficiency over conventional devices by using less write energy, while having a design that is simpler and more scalable than conventional devices. The disclosed devices also have increased thermal stability without increasing required switching current, as critical switching current between states is essentially the same.

Abstract: The present invention is directed to a spin-orbitronics device including a magnetic comparison layer structure having a pseudo-invariable magnetization direction; a magnetic free layer structure whose variable magnetization direction can be switched by a switching current passing between the magnetic comparison layer structure and the magnetic free layer structure; an insulating tunnel junction layer interposed between the magnetic comparison layer structure and the magnetic free layer structure; and a non-magnetic transverse polarizing layer formed adjacent to the magnetic comparison layer structure. The pseudo-invariable magnetization direction of the magnetic comparison layer structure may be switched by passing a comparison current through the transverse polarizing layer along a direction that is substantially parallel to a layer plane of the transverse polarizing layer. The pseudo-invariable magnetization direction of the magnetic comparison layer structure is not switched by the switching current.

Abstract: A look-up table circuit of an embodiment includes: first wiring lines; second wiring lines; resistive change elements disposed to intersection regions of the first and second wiring lines, each resistive change element including a first electrode connected to a corresponding one of the first wiring lines, a second electrode connected to a corresponding one of the second wiring lines; and a resistive change layer disposed between the first electrode and the second electrode; a first controller controlling voltages applied to the first wiring lines; a second controller controlling voltages applied to the second wiring lines; and a multiplexer including input terminals connected to the first wiring lines and an output terminal.

Abstract: Sense circuits, memory devices, and related methods are disclosed. A sense circuit includes sample and hold circuitry configured to sample and hold a second response voltage potential, a first response voltage potential, and a third response voltage potential responsive to an evaluation signal applied to a resistance variable memory cell. The sense circuit includes an amplifier operably coupled to the sample and hold circuitry. The amplifier is configured to amplify a difference between a sum of the first response voltage potential and the third response voltage potential, and twice the second response voltage potential. A memory device includes an evaluation signal generating circuit configured to provide the evaluation signal, an array of resistance variable memory cells, and the sense circuit. A method includes applying the evaluation signal to the resistance variable memory cell, sampling and holding the response voltage potentials, and discharging the sample and hold circuitry to the amplifier.

Abstract: It is an object of the present invention to provide a device which can be easily manufactured and obtain a ground state of an arbitrary Ising model. A semiconductor device includes a first memory cell and a second memory cell that interacts with the first memory cell, in which storage content of the first memory cell and the second memory cell is stochastically inverted. The storage content is stochastically inverted by dropping threshold voltages of the first memory cell and the second memory cell. The threshold voltages of the first and second memory cells are dropping by controlling substrate biases, power voltages, or trip points of the first and second memory cells.

Abstract: Magnetic structures, methods of forming the same, and memory devices including a magnetic structure, include a magnetic layer, and a stress-inducing layer on a first surface of the magnetic layer, a non-magnetic layer on a second surface of the magnetic layer. The stress-inducing layer is configured to induce a compressive stress in the magnetic layer. The magnetic layer has a lattice structure compressively strained due to the stress-inducing layer.

Abstract: A memory device may include a data region, a reference region, a resistor circuit, and a sense amplifier. The data region may include a plurality of data memory cells coupled between a first bit line and a first source line. The data region may provide a data voltage corresponding to data stored in each of the data memory cells. The reference region may include a plurality of reference memory cells coupled between a reference bit line and a reference source line. The reference region may provide a reference voltage. The resistor circuit may include one or more resistors, and is coupled between the reference source line and a power source line. The sense amplifier may provide an output voltage by comparing the data voltage and the reference voltage. The power source line may be either a ground voltage or a negative voltage.

Abstract: Self-referenced magnetic random access memory (MRAM) cell including a magnetic tunnel junction including a sense layer; a storage layer having a storage magnetization; a tunnel barrier layer between the sense and the storage layers; and an antiferromagnetic layer exchange-coupling the storage layer such that the storage magnetization can be pinned when the antiferromagnetic layer is below a critical temperature and freely varied when the antiferromagnetic layer is heated at or above the critical temperature. The sense layer includes a first sense layer having a first sense magnetization, a second sense layer having a second sense magnetization and spacer layer between the first and second sense layers. The MRAM cell can be read with low power consumption.

Abstract: Aspects of the present disclose related to a voltage-controlled magnetic anisotropy (VCMA) switching device using an external ferromagnetic biasing film. Aspects of the present disclose provide for a magnetoresistive random access memory (MRAM) device. The MRAM device generally includes a substrate, at least one magnetic tunnel junction (MTJ) stack disposed on the substrate, wherein the MTJ stack comprises a tunnel barrier layer between a first ferromagnetic layer having a fixed magnetization and a second ferromagnetic layer having unfixed magnetization, and a magnet disposed adjacent to the second ferromagnetic layer.