Abstract: A perpendicular magnetic recording system has a write head having a main helical coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and an auxiliary coil and auxiliary pole that injects magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The auxiliary coil is preferably a helical coil wrapped around the auxiliary pole. The additional flux from the auxiliary pole, which is injected non-parallel to the primary magnetization of the write pole, exerts a relatively large torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. Electrical circuitry is connected to the main coil and the auxiliary coil to generate the auxiliary flux simultaneous with the switching of the magnetization of the write pole.

Abstract: A perpendicular magnetic recording system has a write head having a main coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and an auxiliary coil and auxiliary pole that injects magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The additional flux from the auxiliary pole, which is injected non-parallel to the primary magnetization of the write pole, exerts a relatively large torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. Electrical circuitry is connected to the main coil and the auxiliary coil to generate the auxiliary flux simultaneous with the switching of the magnetization of the write pole.

Abstract: Impedance compensation features are used along the transmission-line path between a transmitter/driver/source and the receiver/transducer to compensate for the impedance discontinuities or mismatches (for example, those caused by physical interconnection features) and/or to improve the frequency response of the signal transfer along the transmission line. The impedance compensation features are non-uniformities with impedance characteristics selected to compensate for the target impedance discontinuities. The compensation features can be non-uniformities (geometric structures designed to have specific impedance characteristics) in the electrically conductive traces that are integrated in the interconnect transmission line between the transmitter/driver/source and the receiver/transducer. The effective impedance level of the transmission line can be lowered or raised using the compensation features.

Abstract: Approaches for a hard-disk drive suspension interconnect having a wide bandwidth. A suspension interconnect includes a substrate layer, a dielectric layer disposed on the substrate layer, and a plurality of transmission-line (TL) conductors disposed within the dielectric layer. Air gaps may be disposed around the TL conductors to minimize the tendency of the dielectric material to act as an electrical shunt, which impedes high bandwidth signal transmission. An air gap may exist in the dielectric layer between adjacent TL conductors. Additionally, the area adjacent to the plurality of TL conductors, along the direction of signal travel, may alternate between dielectric material and air gaps. Indeed, there need not be any solid material enclosing the TL conductors save for a plurality of dielectric cross ties that provide structural support thereto. The substrate layer may also comprise one or more air gaps underneath a portion of the plurality of TL conductors.

Abstract: Write enhancement circuitry on the head carrier of a magnetic recording disk drive provides additional write current overshoot beyond that provided by the write driver circuitry. An enhancement capacitor is formed with a dielectric layer between two layers of electrically-conductive magnetically-permeable shield material that serve as the capacitor plates. The write enhancement circuitry may also include an enhancement resistor. The enhancement capacitor and resistor are connected between the two terminals on the head carrier that connect to the write head coil. The capacitor and resistor are fabricated on the head carrier at the same time and in the same process as the read head. The first and second capacitor plates are generally coplanar with and formed of the same electrically-conductive magnetically-permeable material that forms the first and second magnetic shields for the read head.

Abstract: An interconnect between the write driver and the write head in a magnetic recording disk drive enables an inherent write current overshoot. The interconnect includes an integrated lead suspension (ILS) and a short flex cable that connects the write driver circuitry to the ILS. The interconnect is a two-segment transmission line, with the first segment connected to the write driver having multiple sub-segments or sections with non-uniform impedance levels. The section of the first segment that connects to the write driver is the short flex cable and has an impedance substantially higher than the source impedance ZWD of the write driver. The multiple sections of the first segment have non-uniform impedance values that have an effective impedance Z01-eff that substantially matches ZWD. The second segment of the transmission line has an effective impedance Z02-eff that is substantially less than Z01-eff. The write lines for the +W and ?W signals are preferably interleaved on the transmission line sections.

Abstract: An integrated lead suspension (ILS) in a magnetic recording disk drive has the transmission line portion of the ILS between the flex cable and the gimbal formed of multiple interconnected segments, each with its own characteristic impedance. At the interface between any two segments there is a change in the widths of the electrically conductive traces of the transmission line. The change in impedance of a fixed-length segment is a function of the change in its trace width. The number of segments and their characteristic impedance values are selected to produce the largest frequency bandwidth with a substantially flat group delay from the write driver to the write head.

Abstract: Write enhancement circuitry on the head carrier of a magnetic recording disk drive provides additional write current overshoot beyond that provided by the write driver circuitry. An enhancement capacitor is formed with a dielectric layer between two layers of electrically-conductive magnetically-permeable shield material that serve as the capacitor plates. The write enhancement circuitry may also include an enhancement resistor. The enhancement capacitor and resistor are connected between the two terminals on the head carrier that connect to the write head coil. The capacitor and resistor are fabricated on the head carrier at the same time and in the same process as the read head. The first and second capacitor plates are generally coplanar with and formed of the same electrically-conductive magnetically-permeable material that forms the first and second magnetic shields for the read head.

Abstract: A perpendicular magnetic recording system has a write head having a main coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and a transverse auxiliary pole (TAP) that injects auxiliary magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The additional flux from the TAP, which is injected non-parallel to the primary magnetization of the write pole, exerts a torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. The TAP is coupled to the main coil but not electrically connected to it. A separate passive coil, not electrically connected to the main coil, may be wrapped as a loop around the main pole and the TAP. Alternatively, the TAP may be located near one of the electrically conductive turns of the main coil.

Abstract: A perpendicular magnetic recording hard disk drive includes a write head with a write pole and an electrically conductive coil coupled to the write pole, a write driver for supplying electrical write current to the coil to generate magnetic flux in the write pole, a spin torque oscillator (STO) that injects auxiliary magnetic flux to the write pole to facilitate magnetization switching of the write pole, and STO control circuitry. Direct electrical current to the STO induces rotation of the magnetization of a free ferromagnetic layer in the STO, which generates the auxiliary magnetic flux. The STO control circuitry may be coupled to the STO via the electrical lines that connect the write driver to the write head, the lines that connect the read amplifier to the read head, or, if the disk drive is one with thermal fly-height control (TFC), the lines that connect the TFC circuitry with the heater.

Abstract: A perpendicular magnetic recording write head that a write pole, an electrically conductive coil coupled to the write pole for generating magnetic flux in the write pole in the presence of electrical write current, and a spin torque oscillator (STO) that injects auxiliary magnetic flux to the write pole in a direction generally orthogonal to the write pole to facilitate magnetization switching of the write pole. The STO comprises a stack of layers including electrodes, a pinned ferromagnetic layer having a fixed, a free ferromagnetic layer having a magnetization free to rotate, and a nonmagnetic spacer layer between the pinned and free layers. The free layer may be oriented either substantially orthogonal to the write pole or substantially parallel to the write pole, in which latter embodiment a flux guide may be located between the free layer and the write pole for directing the auxiliary magnetic flux from the free layer to the write pole.

Abstract: A perpendicular magnetic recording system has a write head having a main helical coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and an auxiliary coil and auxiliary pole that injects magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The auxiliary coil is preferably a helical coil wrapped around the auxiliary pole. The additional flux from the auxiliary pole, which is injected non-parallel to the primary magnetization of the write pole, exerts a relatively large torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. Electrical circuitry is connected to the main coil and the auxiliary coil to generate the auxiliary flux simultaneous with the switching of the magnetization of the write pole.

Abstract: A perpendicular magnetic recording system has a write head having a main coil (the write coil) and main pole (the write pole) that directs write flux in a direction perpendicular to the recording layer in the magnetic recording medium, and an auxiliary coil and auxiliary pole that injects magnetic flux into the write pole at an angle to the primary or perpendicular axis of the write pole. The additional flux from the auxiliary pole, which is injected non-parallel to the primary magnetization of the write pole, exerts a relatively large torque on the magnetization of the write pole, thereby facilitating magnetization reversal of the write pole. Electrical circuitry is connected to the main coil and the auxiliary coil to generate the auxiliary flux simultaneous with the switching of the magnetization of the write pole.

Abstract: A signaling apparatus and method are described that use reflected signals to increase the total current delivered to a receiver. Dynamic source-side transmission line termination control is employed to generate reflected signals that constructively add to a nonreflected signal to enhance the signal at the receiver. Switching controls selectively connect and disconnect the transmission line source-side termination resistors to either provide signal termination or remove it. Driver designs using either voltage or current sources for use in signaling systems (including, for example, magnetic storage devices with inductive coil based write heads) are described.

Abstract: A perpendicular magnetic recording system has a write head with a main perpendicular write pole connected to a yoke with first and second electrical coils. The first coil is wrapped around the yoke on one side of the main pole, and the second coil is wrapped around the yoke on the other side of the main pole. The first end of each coil is connected to a respective terminal. The second ends of the two coils are connected together and connected to a common terminal. A lead-time circuit is connected between the common terminal and the first end of one of the coils. Immediately after the direction of write current is switched by the write driver, the lead-time circuit causes the current in one of the coils to lead the current in the other coil. The current displacement between the two coils creates a precession of the magnetic flux reversal, thereby reducing the switching time of the write head.

Abstract: Impedance compensation features are used along the transmission-line path between a transmitter/driver/source and the receiver/transducer to compensate for the impedance discontinuities or mismatches (for example, those caused by physical interconnection features) and/or to improve the frequency response of the signal transfer along the transmission line. The impedance compensation features are non-uniformities with impedance characteristics selected to compensate for the target impedance discontinuities. The compensation features can be non-uniformities (geometric structures designed to have specific impedance characteristics) in the electrically conductive traces that are integrated in the interconnect transmission line between the transmitter/driver/source and the receiver/transducer. The effective impedance level of the transmission line can be lowered or raised using the compensation features.

Abstract: A signaling apparatus and method are described that use reflected signals to increase the total current delivered to a receiver. Dynamic source-side transmission line termination control is employed to generate reflected signals that constructively add to a nonreflected signal to enhance the signal at the receiver. Switching controls selectively connect and disconnect the transmission line source-side termination resistors to either provide signal termination or remove it. Driver designs using either voltage or current sources for use in signaling systems (including, for example, magnetic storage devices with inductive coil based write heads) are described.

Abstract: An integrated lead suspension (ILS) or flexure has a connection scheme that allows for coplanar and interleaved conductive traces between read/write circuitry and a read/write head in a magnetic recording disk drive. The flexure has an electrically conductive substrate and insulator layer with the traces formed on the insulator layer. At each end of the flexure there is an island of substrate material with vias in the insulator layer that permit electrical connection to the islands. The conductive traces are grouped into two sets and extend generally parallel along the length of the flexure, with the traces from one set being interleaved with traces from the other set and each set carrying one of the positive or negative signals. At one of the ends, all of the traces from one set are connected through the vias to the island at that end, and at the other end all of the traces from the other set are connected through the vias to the island at that end.

Abstract: Circuits and methods are provided for write through drivers in disk drive systems. A write through driver is a transceiver that includes a write driver circuit and a receiver circuit. The write driver drives a current signal to a write element through a first conductive interconnect. The write element writes data patterns to a magnetic hard disk in response to the current signal from the write driver circuit. The current signal returns to the receiver circuit through a second conductive interconnect. The return signal can be used for the diagnosis of write-safe conditions.

Abstract: An electrical lead suspension (ELS) having partitioned air slots. The ELS includes a laminate. A first plurality of signal traces and a second plurality of traces are in a first formed layer of the laminate. The second plurality of traces may be signal traces or power traces. The laminate has a dielectric layer between the first formed layer and a second formed layer. A plurality of partitioned air slots is in the second formed layer of the laminate. The portion of the ELS having a plurality of partitioned air slots supporting the at least the first plurality of signal traces and the portion of the ELS having a second plurality of partitioned air slots or patterns supporting the second plurality of traces. The supporting of the first plurality of signal traces separate from the second plurality of traces reduces write-to-read cross talk and signal loss.