Abstract: A magnetoresistive memory array including a plurality of magnetoresistive memory elements wherein each magnetoresistive memory element comprises a free layer including at least one ferromagnetic layer having perpendicular magnetic anisotropy, a fixed layer, and a tunnel barrier, disposed between and in contact with the free and fixed layers. The tunnel barrier includes a first metal-oxide layer, having a thickness between 1 and 10 Angstroms, a second metal-oxide layer, having a thickness between 3 and 6 Angstroms, disposed on the first metal-oxide layer, and a third metal-oxide layer, having a thickness between 3 and 6 Angstroms, disposed over the second metal-oxide layer. In one embodiment, the third metal-oxide layer is in contact with the free layer or fixed layer. The tunnel barrier may also include a fourth metal-oxide layer, having a thickness between 1 and 10 Angstroms, disposed between the second and third metal-oxide layers.

Abstract: A magnetoresistive memory element (e.g., a spin-torque magnetoresistive memory element) includes a fixed magnetic layer, a free magnetic layer having perpendicular magnetic anisotropy, and a first dielectric, disposed between the fixed magnetic layer and the free magnetic layer. A first surface of the first dielectric is in contact with a first surface of the free magnetic layer. The magnetoresistive memory element further includes a second dielectric, having a first surface that is in contact with a second surface of the free magnetic layer, a conductor, including electrically conductive material, and an electrode, disposed between the second dielectric and the conductor. The electrode includes: (i) a non-ferromagnetic portion having a surface that is in contact with a second surface of the second dielectric, and (ii) a second portion including at least one ferromagnetic material disposed between the non-ferromagnetic portion of the electrode and the conductor.

Abstract: In some examples, a memory device may be configured to store data in either an original or an inverted state based at least in part on a state associated with one or more shorted bit cells. For instance, the memory device may be configured to identify a shorted bit cell within a memory array and to store the data in the memory array, such that a state of the data bit stored in the shorted bit cell matches the state associated with the shorted bit cell.

Abstract: A memory device is configured to identify a set of bit cells to be changed from a first state to a second state. In some examples, the memory device may apply a first voltage to the set of bit cells to change a least a first portion of the set of bit cells to the second state. In some cases, the memory device may also identify a second portion of the bit cells that remained in the first state following the application of the first voltage. In these cases, the memory device may apply a second voltage having a greater magnitude, duration, or both to the second portion of the set of bit cells in order to set the second portion of bit cells to the second state.

Abstract: In one aspect, the present inventions are directed to a magnetoresistive structure having a tunnel junction, and a process for manufacturing such a structure. The tunnel barrier may be formed between a free layer and a fixed layer in a plurality of repeating process of depositing a metal material and oxidizing at least a portion of the metal material. Where the tunnel barrier is formed by deposition of at least three metal materials interceded by an associated oxidization thereof, the oxidation dose associated with the second metal material may be greater than the oxidation doses associated with the first and third metal materials. In certain embodiments, the fixed layer may include a discontinuous layer of a metal, for example, Ta, in the fixed layer between two layers of a ferromagnetic material.

Abstract: An architecture and method includes providing an oscillatory signal through each magnetic tunnel junction (MTJ), or in a line adjacent each MTJ, in a magnetoresistive random access memory array. A rectified signal appearing across each MTJ is measured and compared to a reference signal for determining the state of the MTJ.

Abstract: Circuitry and a method provide an increased tunnel barrier endurance (lifetime) previously shortened by dielectric breakdown by providing a pulse of opposite polarity associated with a write pulse. The pulse of opposite polarity may comprise equal or less width and amplitude than that of the write pulse, may be applied with each write pulse or a series of write pulses, and may be applied prior to or subsequent to the write pulse.

Abstract: Techniques and circuits for testing and configuring magnetic memory devices are presented. Registers and nonvolatile storage is included on the memory devices for storing values used to control testing of the memory devices as well as for configuring parameters related to both testing and normal operation. Examples include adjustment of bias voltages, sense amplifier offset values, and timing parameters to improve the efficiency of testing operations as well as improve reliability and speed of normal operation.

Abstract: Memory cells in a spin-torque magnetic random access memory (MRAM) include at least two magnetic tunnel junctions within each memory cell, where each memory cell only stores a single data bit of information. Access circuitry coupled to the memory cells are able to read from and write to a memory cell even when one of the magnetic tunnel junctions within the memory cell is defective and is no longer functional. Self-referenced and referenced reads can be used in conjunction with the multiple magnetic tunnel junction memory cells. In some embodiments, writing to the memory cell forces all magnetic tunnel junctions into a known state, whereas in other embodiments, a subset of the magnetic tunnel junctions are forced to a known state.

Abstract: A magnetoresistive memory element (for example, a spin-torque magnetoresistive memory element), includes first and second dielectric layers, wherein at least one of the dielectric layers is a magnetic tunnel junction. The memory element also includes a free magnetic layer having a first surface in contact with the first dielectric layer and a second surface in contact with the second dielectric layer. The free magnetic layer, which is disposed between the first and second dielectric layers, includes (i) a first high-iron interface region located along the first surface of the free magnetic layer, wherein the first high-iron interface region has at least 50% iron by atomic composition, and (ii) a first layer of ferromagnetic material adjacent to the first high-iron interface region, the first high-iron interface region between the first layer of ferromagnetic material and the first surface of the free magnetic layer.

Abstract: A spin-torque magnetoresistive memory element has a high magnetoresistance and low current density. A free magnetic layer is positioned between first and second spin polarizers. A first tunnel barrier is positioned between the first spin polarizer and the free magnetic layer and a second tunnel barrier is positioned between the second spin polarizer and the free magnetic layer. The magnetoresistance ratio of the second tunnel barrier has a value greater than double the magnetoresistance ratio of the first tunnel barrier.

Abstract: An MRAM device, and a process for manufacturing the device, provides improved breakdown distributions, a reduced number of bits with a low breakdown voltage, and an increased MR, thereby improving reliability, manufacturability, and error-free operation. A tunnel barrier is formed between a free layer and a fixed layer in three repeating steps of forming a metal material, interceded by oxidizing each of the metal materials. The oxidization of the third metal material is greater than the dose of the first metal, but less than the dose of the second metal. The fixed layer may include a discontinuous layer of a metal, for example, Ta, in the fixed layer between two layers of a ferromagnetic material.

Abstract: In one aspect, the present inventions are directed to a magnetoresistive structure having a tunnel junction, and a process for manufacturing such a structure. The tunnel barrier may be formed between a free layer and a fixed layer in a plurality of repeating process of depositing a metal material and oxidizing at least a portion of the metal material. Where the tunnel barrier is formed by deposition of at least three metal materials interceded by an associated oxidization thereof, the oxidation dose associated with the second metal material may be greater than the oxidation doses associated with the first and third metal materials. In certain embodiments, the fixed layer may include a discontinuous layer of a metal, for example, Ta, in the fixed layer between two layers of a ferromagnetic material.

Abstract: Circuitry and a method provide an increased tunnel barrier endurance (lifetime) previously shortened by dielectric breakdown by providing a pulse of opposite polarity associated with a write pulse. The pulse of opposite polarity may comprise equal or less width and amplitude than that of the write pulse, may be applied with each write pulse or a series of write pulses, and may be applied prior to or subsequent to the write pulse.

Abstract: The invention relates to a radiofrequency oscillator which incorporates: a spin-polarized electric current magnetoresistive device (6), a terminal (18) for controlling the frequency or amplitude of the oscillating signal, a servo loop (34) connected between the output terminal and the control terminal for applying a control signal to the control terminal in order to slave a characteristic of the oscillating signal to a reference value, the servo loop (34) comprising: a sensor (36) of the amplitude of the oscillating signal oscillations, and a comparator (38) capable of generating the control signal according to the measured amplitude and the reference value.

Abstract: A method is provided for healing reset errors for a magnetic memory using destructive read with selective write-back, including for example, a self-referenced read of spin-torque bits in an MRAM. Memory cells are prepared for write back by one of identifying memory cells determined in error using an error correcting code and inverting the inversion bit for those memory cells determined in error; identifying memory cells determined in error using an error correcting code and resetting a portion of the memory cells to the first state; and resetting one or more memory cells to the first state.

Abstract: The invention relates to a radiofrequency oscillator which incorporates: a spin-polarized electric current magnetoresistive device (6) for generating an oscillating signal at an oscillation frequency on an output terminal (10), and a terminal (18) for controlling the frequency or amplitude of the oscillating signal, and a feedback loop (44) comprising an amplifier (46) provided with: an input connected to the output terminal (10) of the magnetoresistive device (6) so as to amplify the portion of an oscillating signal detected at the output terminal, and an output connected to the control terminal (18) so as to inject onto said control terminal the amplified portion of the oscillating signal which is phase-related to the oscillating signal generated at the output terminal.

Abstract: A spin-torque magnetoresistive memory element has a high magnetoresistance and low current density. A free magnetic layer is positioned between first and second spin polarizers. A first tunnel barrier is positioned between the first spin polarizer and the free magnetic layer and a second tunnel barrier is positioned between the second spin polarizer and the free magnetic layer. The magnetoresistance ratio of the second tunnel barrier has a value greater than double the magnetoresistance ratio of the first tunnel barrier.

Abstract: A radiofrequency oscillator comprises: a free layer (4), a current injector (6) for injecting spin-polarized current into the free layer, this injector having a spin-polarized current injection face (16) directly in contact with the free layer, a magnetoresistive contact (8) having a measurement face (26) directly in contact with the free layer, in order to form, in combination with the free layer, a tunnel junction for measuring the precession of the magnetization of the free layer, a conducting pad (30) directly in contact with the free layer in order to make an electrical current flow through the injector without passing through the magnetoresistive contact. At least part of the measurement face (26) and part of the injection face (16) are placed facing each other on each side of the free layer (4).

Abstract: A spin-torque magnetoresistive memory element has a high magnetoresistance and low current density. A free magnetic layer is positioned between first and second spin polarizers. A first tunnel barrier is positioned between the first spin polarizer and the free magnetic layer and a second tunnel barrier is positioned between the second spin polarizer and the free magnetic layer. The magnetoresistance ratio of the second tunnel barrier has a value greater than double the magnetoresistance ratio of the first tunnel barrier.