# US 2015/0103437 A1 · Microwave- assisted recording head with stable oscillation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2015/0103437 A1 - Document ID: US20150103437A1 - Status: Published application - Kind: A1 - Application number: 14/055,769 - Filed: 2013-10-16 - Published: 2015-04-16 - Earliest claimed: 2013-10-16 - Assignees: HGST Netherlands B.V. - Applicants: HGST Netherlands B.V. - Inventors: Katsuro Watanabe; Yohji Maruyama - Web page: https://patentgrep.com/patent/US20150103437A1 ## CPC - G11B 5/02: Recording, reproducing, or erasing methods; Read, write or erase circuits therefor - G11B 5/1278: {specially adapted for magnetisations perpendicular to the surface of the record carrier} - G11B 5/3133: {including layers not usually being a part of the electromagnetic transducer structure and providing additional features, e.g. for improving heat radiation, reduction of power dissipation, adaptations for measurement or indication of gap depth or other properties of the structure (G11B5/3106 takes precedence)} - G11B 5/3146: {magnetic layers} - G11B 5/40: Protective measures on heads, e.g. against excessive temperature (G11B5/31 takes precedence; protection against wear G11B5/255 {; protective structure of the head: see under structures, e.g. G11B5/3106}) - G11B 2005/0024: {Microwave assisted recording} - G11B: INFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER (recording measured values in a way that does not require playback through a transducer G01D9/00; recording or playback apparatus using mechanically marked tape, e.g. punched paper tape, or using unit records, e.g. punched or magnetically marked cards G06K; transferring data from one type of record carrier to another G06K1/18; circuits for coupling output of reproducer to radio receiver H04B1/20; gramophone pick-ups or like acoustic electromechanical transducers or circuits therefor H04R) ## Abstract A magnetic recording head for microwave-assisted magnetic recording is disclosed. In one embodiment, a magnetic recording head is for applying a magnetic field from a main pole of said magnetic recording head for recording data to a disk. Further comprising a spin torque oscillator adjacent to said magnetic recording head and is for generating a high-frequency magnetic field at a stable frequency and amplitude. Further comprising a capacitor connected to an upper electrode of said spin torque oscillator via a first resistor and a lower electrode of said spin torque oscillator via a second resistor. ## Claims ### Claim 1 A magnetic recording head for microwave-assisted magnetic recording, comprising: a magnetic recording head for applying a magnetic field from a main pole of said magnetic recording head for recording data to a disk; a spin torque oscillator adjacent to said magnetic recording head for generating a high-frequency magnetic field at a stable frequency and amplitude; and a capacitor connected to an upper electrode of said spin torque oscillator via a first resistor and a lower electrode of said spin torque oscillator via a second resistor. ### Claim 2 (depends on 1) The magnetic recording head as recited in claim 1 wherein said magnetic recording head accomplishes said recording data to said disk by taking a lower limit frequency for said recording as fw—L, a resistance value of said first resistor and said second resistor as R, and a capacitance of said capacitor as C, a product RC of R and C is RC>1/(2πfw—L). ### Claim 3 (depends on 1) The magnetic recording head as recited in claim 1 wherein a portion of said upper electrode of said spin torque oscillator constitutes an upper pole and a portion of said lower electrode of said spin torque oscillator constitutes a main pole. ### Claim 4 (depends on 1) The magnetic recording head as recited in claim 1 wherein one of either said upper electrode or said lower electrode of the spin torque oscillator is electrically grounded. ### Claim 5 (depends on 1) The magnetic recording head as recited in claim 1 wherein a ratio of a parasitic capacitance pertaining to said upper electrode to said lower electrode of said spin torque oscillator is between 0.6 and 1.4. ### Claim 6 (depends on 1) The magnetic recording head as recited in claim 1 wherein a ratio of a parasitic capacitance ratio pertaining to said upper electrode to said lower electrode of said spin torque oscillator is between 0.9 and 1.1. ### Claim 7 (depends on 1) The magnetic recording head as recited in claim 1 wherein a helical coil is wound around said main pole. ### Claim 8 (depends on 1) The magnetic recording head as recited in claim 1 wherein separate coils of a dual pancake coil are wound above and below said main pole. ### Claim 9 A disk drive for microwave-assisted magnetic recording, comprising: a housing; a disk in said housing for storing data; a magnetic recording head for applying a magnetic field from a main pole of said magnetic recording head for recording said data to said disk; a spin torque oscillator adjacent to said magnetic recording head for generating a high-frequency magnetic field at a stable frequency and amplitude; and a capacitor connected to an upper electrode of said spin torque oscillator via a first resistor and a lower electrode of said spin torque oscillator via a second resistor. ### Claim 10 (depends on 9) The magnetic recording head as recited in claim 9 wherein said magnetic recording head accomplishes said recording data to said disk by taking a lower limit frequency for said recording as fw—L, a resistance value of said first resistor and said second resistor as R, and a capacitance of said capacitor as C, a product RC of R and C is RC>1/(2πfw—L). ### Claim 11 (depends on 9) The magnetic recording head as recited in claim 9 wherein a portion of said upper electrode of said spin torque oscillator constitutes an upper pole and a portion of said lower electrode of said spin torque oscillator constitutes a main pole. ### Claim 12 (depends on 9) The magnetic recording head as recited in claim 9 wherein one of either said upper electrode or said lower electrode of the spin torque oscillator is electrically grounded. ### Claim 13 (depends on 9) The magnetic recording head as recited in claim 9 wherein a ratio of a parasitic capacitance pertaining to said upper electrode to said lower electrode of said spin torque oscillator is between 0.6 and 1.4. ### Claim 14 (depends on 9) The magnetic recording head as recited in claim 9 wherein a ratio of a parasitic capacitance pertaining to said upper electrode to said lower electrode of said spin torque oscillator is between 0.9 and 1.1. ### Claim 15 (depends on 9) The magnetic recording head as recited in claim 9 wherein a helical coil is wound around said main pole. ### Claim 16 (depends on 9) The magnetic recording head as recited in claim 9 wherein separate coils of a dual pancake coil are wound above and below said main pole. ### Claim 17 A magnetic recording head for microwave-assisted magnetic recording, comprising: a magnetic recording head for applying a magnetic field from a main pole of said magnetic recording head for recording data to a disk; a spin torque oscillator adjacent to said magnetic recording head for generating a high-frequency magnetic field at a stable frequency and amplitude; and a capacitor connected to an upper electrode of said spin torque oscillator via a first resistor and a lower electrode of said spin torque oscillator via a second resistor, and wherein a portion of said upper electrode of said spin torque oscillator constitutes an upper pole and a portion of said lower electrode of said spin torque oscillator constitutes a main pole. ### Claim 18 (depends on 17) The magnetic recording head as recited in claim 17 wherein said magnetic recording head accomplishes said recording data to said disk by taking a lower limit frequency for said recording as fw—L, a resistance value of said first resistor and said second resistor as R, and a capacitance of said capacitor as C, a product RC of R and C is RC>1/(2πfw—L). ### Claim 19 (depends on 9) The magnetic recording head as recited in claim 9 wherein one of either said upper electrode or said lower electrode of the spin torque oscillator is electrically grounded. ### Claim 20 (depends on 9) The magnetic recording head as recited in claim 9 wherein a ratio of a parasitic capacitance ratio pertaining to said upper electrode to said lower electrode of said spin torque oscillator is between 0.6 and 1.4.