# US 10,482,939 B2 · Magnetic memory device and method of writing magnetic memory device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,482,939 B2 - Document ID: US10482939B2 - Status: Granted - Kind: B2 - Application number: 15/822,877 - Filed: 2017-11-27 - Published: 2018-05-31 - Granted: 2019-11-19 - Earliest claimed: 2016-11-29 - Assignees: Samsung Electronics Co., Ltd.; Korea University Research and Business Foundation - Applicants: Samsung Electronics Co., Ltd.; KOREA UNIVERSITY Research and Business Foundation - Inventors: Woo Chang Lim; Kyung-Jin Lee; Gyungchoon Go; Seung-Jae Lee - Web page: https://patentgrep.com/patent/US10482939B2 ## CPC - G11C 11/16: using elements in which the storage effect is based on magnetic spin effect - G11C 11/15: using multiple magnetic layers (G11C11/155 takes precedence) - G11C 11/161: {details concerning the memory cell structure, e.g. the layers of the ferromagnetic memory cell} - G11C 11/1675: {Writing or programming circuits or methods} - G11C 11/1693: {Timing circuits or methods} - H10B 61/00: Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices - H10N 50/10: Magnetoresistive devices - H10N 50/80: Constructional details - G11C: STATIC STORES (semiconductor memory devices H10B) - H10B: ELECTRONIC MEMORY DEVICES - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract Embodiments provide a magnetic memory device and a method of writing a magnetic memory device. The magnetic memory device includes a magnetic tunnel junction including a reference layer, a free layer and a tunnel barrier layer between the reference and free layers, and a first conductive line adjacent to the free layer. A first spin-orbit current having a frequency decreasing with time flows through the first conductive line. The writing method includes applying the first spin-orbit current having the frequency decreasing with time to the first conductive line. ## Claims ### Claim 1 A method of writing a magnetic memory device including a magnetic tunnel junction having a free layer, a reference layer, and a tunnel barrier layer between the free layer and the reference layer, and a first conductive line adjacent to the free layer, the method comprising: applying a first spin-orbit current to the first conductive line, the first spin-orbit current being an alternating current, and during applying, decreasing a frequency of the first spin-orbit current over time in a fixed manner. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein: the magnetic tunnel junction is on a first surface of the first conductive line, and the free layer is between the tunnel barrier layer and the first surface of the first conductive line. ### Claim 3 (depends on 1) The method as claimed in claim 1, wherein applying the first spin-orbit current applies a spin-orbit torque to a magnetic moment of the free layer. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein: the first spin-orbit current has an initial frequency when applying the first spin-orbit current starts, a magnetic moment of the free layer has an initial natural frequency when applying the first spin-orbit current starts, and the initial frequency of the first spin-orbit current is equal to or greater than the initial natural frequency of the magnetic moment of the free layer. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein applying the first spin-orbit current generates at least two resonances at which a frequency of the first spin-orbit current coincides with a natural frequency of a magnetic moment of the free layer. ### Claim 6 (depends on 5) The method as claimed in claim 5, wherein the frequency of the first spin-orbit current is greater than the natural frequency of the magnetic moment of the free layer between the at least two resonances. ### Claim 7 (depends on 1) The method as claimed in claim 1, further comprising: applying a spin-transfer current passing through the magnetic tunnel junction. ### Claim 8 (depends on 7) The method as claimed in claim 7, wherein the spin-transfer current is applied after the applying of the first spin-orbit current. ### Claim 9 (depends on 7) The method as claimed in claim 7, wherein the spin-transfer current and the first spin-orbit current are applied at the same time for at least a certain period of time. ### Claim 10 (depends on 1) The method as claimed in claim 1, wherein the magnetic memory device further comprises: a second conductive line intersecting the first conductive line, the method further comprising: applying a second spin-orbit current having a frequency decreasing with time to the second conductive line. ### Claim 11 (depends on 10) The method as claimed in claim 10, wherein the magnetic tunnel junction is disposed on a crossing point of the first and second conductive lines. ### Claim 12 (depends on 10) The method as claimed in claim 10, wherein the frequency of the first spin-orbit current is equal to the frequency of the second spin-orbit current. ### Claim 13 (depends on 1) The method as claimed in claim 1, wherein applying the first spin-orbit current includes initially applying the first spin-orbit current having an initial frequency at a first time to the first conductive line; and subsequently applying the first spin-orbit current having a subsequent frequency, less than the initial frequency, at a second time to the first conductive line, the second time after the first time. ### Claim 14 (depends on 13) The method as claimed in claim 13, wherein: a magnetic moment of the free layer has an initial natural frequency when applying the first spin-orbit current starts, and the initial frequency of the first spin-orbit current is equal to or greater than the initial natural frequency of the magnetic moment of the free layer. ### Claim 15 (depends on 13) The method as claimed in claim 13, further comprising: applying a spin-transfer current passing through the magnetic tunnel junction. ### Claim 16 (depends on 13) The method as claimed in claim 13, wherein applying the first spin-orbit current generates at least two resonances at which a frequency of the first spin-orbit current coincides with a natural frequency of a magnetic moment of the free layer.