# US 9,520,552 B2 · DIOMEJ cell device > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,520,552 B2 - Document ID: US9520552B2 - Status: Granted - Kind: B2 - Application number: 14/458,451 - Filed: 2014-08-13 - Published: 2016-11-17 - Granted: 2016-12-13 - Earliest claimed: 2012-09-08 - Assignees: The Regents of the University of California - Applicants: The Regents of the University of California - Inventors: Pedram Khalili Amiri; Kang L. Wang - Web page: https://patentgrep.com/patent/US9520552B2 ## CPC - H10B 61/10: {comprising components having two electrodes, e.g. diodes or MIM elements} - 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 11/18: using Hall-effect devices - H10B 61/00: Magnetic memory devices, e.g. magnetoresistive RAM [MRAM] devices - H10B 61/20: {comprising components having three or more electrodes, e.g. transistors} - H10N 50/10: Magnetoresistive devices - H10N 50/80: Constructional details - H10N 50/85: Materials of the active region - H10B: ELECTRONIC MEMORY DEVICES - G11C: STATIC STORES (semiconductor memory devices H10B) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract Embodiments of the technology implement DIOMEJ cells. In one embodiment, a DIOMEJ cell includes: an MEJ that includes, a ferromagnetic fixed layer, a ferromagnetic free layer, and a dielectric layer interposed between said fixed and free layers, where the fixed layer is magnetically polarized in a first direction, where the free layer has a first easy axis that is aligned with the first direction, and where the MEJ is configured such that when a potential difference is applied across it, the magnetic anisotropy of the free layer is altered such that the relative strength of the magnetic anisotropy along a second easy axis that is orthogonal to the first easy axis, as compared to the strength of the magnetic anisotropy along the first easy axis, is magnified for the duration of the application of the potential difference; and a diode, where the diode and the MEJ are arranged in series. ## Claims ### Claim 1 A DIOMEJ cell apparatus comprising: (a) an access device; and (b) a magnetoelectric junction coupled to the access device, the magnetoelectric junction comprising: (i) a ferromagnetic fixed layer magnetically polarized in a first direction; (ii) a ferromagnetic free layer with an easy magnetic axis that is substantially aligned with the first direction, such that the ferromagnetic free layer can adopt a magnetic polarity that is either parallel with or anti-parallel with the first direction; and (iii) a non-magnetic layer interposed between said ferromagnetic fixed layer and said ferromagnetic free layer; (iv) wherein the coercivity of the ferromagnetic free layer is reduced when a potential difference is applied across the magnetoelectric junction; and (c) wherein the access device and the magnetoelectric junction are connected in series. ### Claim 2 (depends on 1) The apparatus as recited in claim 1, wherein said access device is a diode selected from the group consisting of a Schottky diode, a zener diode, an avalanche diode, and a tunnel diode. ### Claim 3 (depends on 1) The apparatus as recited in claim 1, further comprising a transistor selected from the group of transistors consisting of a PMOS transistor, an NMOS transistor, a CMOS transistor and a JFET transistor; wherein the transistor, the access device and the magnetoelectric junction are connected in series. ### Claim 4 (depends on 1) The apparatus as recited in claim 1, wherein said non-magnetic layer of the magnetoelectric junction comprises a dielectric material. ### Claim 5 (depends on 1) The apparatus as recited in claim 1, said magnetoelectric junction further comprising: a first layer of a non-magnetic material coupled to the ferromagnetic fixed layer and to the ferromagnetic free layer; and a second layer of a dielectric material coupled to the ferromagnetic free layer; wherein first and second layers of non-magnetic material are adjoined to opposing sides of the ferromagnetic free layer. ### Claim 6 (depends on 1) The apparatus as recited in claim 1, said magnetoelectric junction further comprising a seed layer of a material selected from the group of materials consisting of Tantalum, Hafnium, Ruthenium and Palladium or combinations thereof. ### Claim 7 (depends on 1) The apparatus as recited in claim 1, said magnetoelectric junction further comprising: a semi-fixed layer coupled to the non-magnetic layer; and a second non-magnetic layer coupled to the semi-fixed layer; wherein the second non-magnetic layer is interposed between the ferromagnetic free layer and the semi-fixed layer; and wherein the semi-fixed layer has a direction of magnetic polarization that is anti-parallel with the direction of magnetic polarization of the ferromagnetic fixed layer. ### Claim 8 (depends on 1) The apparatus as recited in claim 1, further comprising at least one metal layer interposed between the access device and the magnetoelectric junction. ### Claim 9 (depends on 1) The apparatus as recited in claim 1, further comprising: a first electrode coupled to the access device; a second electrode coupled to the magnetoelectric junction; and a substrate supporting the second electrode. ### Claim 10 (depends on 1) The apparatus as recited in claim 1: wherein said access device and said magnetoelectric junction have an elliptical cross-sectional shape; and wherein the ratio of the long diameter to the short diameter is within the range of 3.5 to 1.5. ### Claim 11 (depends on 1) The apparatus as recited in claim 1, wherein said access device has a circular cross-sectional shape and said magnetoelectric junction has a hexagonal cross-sectional shape. ### Claim 12 A DIOMEJ cell array, comprising: (a) a plurality of source lines; (b) a plurality of bit lines; and (c) a plurality of DIOMEJ cells electrically coupled to at least one source line and one bit line, each DIOMEJ cell comprising: (i) a an access device; and (ii) a magnetoelectric junction coupled to the access device, the magnetoelectric junction comprising: (iii) a ferromagnetic fixed layer magnetically polarized in a first direction; (iv) a ferromagnetic free layer with an easy magnetic axis that is substantially aligned with the first direction, such that the ferromagnetic free layer can adopt a magnetic polarity that is either parallel with or anti-parallel with the first direction; and (v) a non-magnetic layer interposed between said ferromagnetic fixed layer and said ferromagnetic free layer; (vi) wherein the coercivity of the ferromagnetic free layer is reduced when a potential difference is applied across the magnetoelectric junction; and (vii) wherein the access device and the magnetoelectric junction are arranged in series. ### Claim 13 (depends on 12) The apparatus as recited in claim 12, further comprising: each DIOMEJ cell is electrically connected to a unique combination of a source line and a bit line, such that no other DIOMEJ cell is connected to the same bit line and the same source line; and wherein a source line and a bit line can be used to establish a potential difference across a particular DIOMEJ cell.