# US 2013/0278346 A1 · Magnetic oscillator > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0278346 A1 - Document ID: US20130278346A1 - Status: Published application - Kind: A1 - Application number: 13/923,062 - Filed: 2013-06-20 - Published: 2013-10-24 - Earliest claimed: 2009-09-29 - Assignees: Kabushiki Kaisha Toshiba - Inventors: Tazumi NAGASAWA; Kiwamu KUDO; Rie SATO; Koichi MIZUSHIMA - Web page: https://patentgrep.com/patent/US20130278346A1 ## CPC - H03B 15/006: {using spin transfer effects or giant magnetoresistance} - G11B 5/3903: {using magnetic thin film layers or their effects, the films being part of integrated structures} - H01F 10/3254: {the spacer being semiconducting or insulating, e.g. for spin tunnel junction [STJ]} - H01F 10/3286: {Spin-exchange coupled multilayers having at least one layer with perpendicular magnetic anisotropy} - H01F 10/329: {Spin-exchange coupled multilayers wherein the magnetisation of the free layer is switched by a spin-polarised current, e.g. spin torque effect} - H10N 50/10: Magnetoresistive devices - G11B 2005/0002: {Special dispositions or recording techniques} - H01F 10/3272: {by use of anti-parallel coupled [APC] ferromagnetic layers, e.g. artificial ferrimagnets [AFI], artificial [AAF] or synthetic [SAF] anti-ferromagnets} - H03B: GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING, BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN A NON-SWITCHING MANNER; GENERATION OF NOISE BY SUCH CIRCUITS (generators adapted for electrophonic musical instruments G10H; masers or lasers H01S; generation of oscillations in plasma H05H) - 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) - H01F: MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract According to one embodiment, a magnetic oscillator includes a layered film and a pair of electrodes. The layered film includes a first ferromagnetic layer, an insulating layer stacked on the first ferromagnetic layer, and a second ferromagnetic layer stacked on the insulating layer. The pair of electrodes is configured to apply a current to the layered film in a direction perpendicular to a film surface of the layered film. Regions having different resistance area products are provided between the first ferromagnetic layer and the second ferromagnetic layer. ## Claims ### Claim 1 A magnetic oscillator comprising: a layered film comprising a first ferromagnetic layer, an insulating layer stacked on the first ferromagnetic layer, and a second ferromagnetic layer stacked on the insulating layer; a pair of electrodes configured to apply a current to the layered film in a direction penetrating a film surface of the layered film; and a metal path which electrically connects the first ferromagnetic layer and the second ferromagnetic layer, wherein regions having different resistance area products are provided in a plane between the first ferromagnetic layer and the second ferromagnetic layer. ### Claim 2 (depends on 1) The oscillator according to claim 1, wherein the metal path is arranged on a sidewall of the layered film. ### Claim 3 (depends on 1) The oscillator according to claim 1, wherein the metal path has a length longer than a thickness of the insulating layer. ### Claim 4 (depends on 1) The oscillator according to claim 1, wherein the current flows through both of the insulating layer and the metal path. ### Claim 5 (depends on 1) The oscillator according to claim 1, wherein the insulating layer is a tunnel barrier. ### Claim 6 (depends on 1) The oscillator according to claim 1, wherein the metal path is not sandwiched between the first ferromagnetic layer and the second ferromagnetic layer. ### Claim 7 (depends on 1) The oscillator according to claim 1, wherein each of the first ferromagnetic layer, the second ferromagnetic layer, and the insulating layer has a cross sectional shape taken along a plane perpendicular to a stacking direction, the cross sectional shape being tapered toward an end part, and the insulating layer is provided with a leak path at the end part, the leak path having a smaller resistance area product than a resistance area product of the insulating layer. ### Claim 8 (depends on 1) The oscillator according to claim 1, wherein the insulating layer includes the regions having different thicknesses. ### Claim 9 A magnetic recording and reproducing apparatus comprising: a magnetic oscillator comprising: a layered film comprising a first ferromagnetic layer, an insulating layer stacked on the first ferromagnetic layer, and a second ferromagnetic layer stacked on the insulating layer; a pair of electrodes configured to apply a current to the layered film in a direction penetrating a film surface of the layered film; and a metal path which electrically connects the first ferromagnetic layer and the second ferromagnetic layer, wherein regions having different resistance area products are provided in a plane between the first ferromagnetic layer and the second ferromagnetic layer. ### Claim 10 (depends on 9) The apparatus according to claim 9, wherein the metal path is arranged on a sidewall of the layered film. ### Claim 11 (depends on 9) The apparatus according to claim 9, wherein the metal path has a length longer than a thickness of the insulating layer. ### Claim 12 (depends on 9) The apparatus according to claim 9, wherein the current flows through both of the insulating layer and the metal path. ### Claim 13 (depends on 9) The apparatus according to claim 9, wherein the insulating layer is a tunnel barrier. ### Claim 14 (depends on 9) The apparatus according to claim 9, wherein the metal path is not sandwiched between the first ferromagnetic layer and the second ferromagnetic layer. ### Claim 15 (depends on 9) The apparatus according to claim 9, wherein each of the first ferromagnetic layer, the second ferromagnetic layer, and the insulating layer has a cross sectional shape taken along a plane perpendicular to a stacking direction, the cross sectional shape being tapered toward an end part, and the insulating layer is provided with a leak path at the end part, the leak path having a smaller resistance area product than a resistance area product of the insulating layer. ### Claim 16 (depends on 9) The apparatus according to claim 9, wherein the insulating layer includes the regions having different thicknesses.