Thermally assisted MRAMs: ultimate scalability and logic functionalities

• Published in: Journal of physics. D, Applied physics Vol. 46; no. 7; pp. 74002 - 1-16
• Main Authors: Prejbeanu, I L, Bandiera, S, Alvarez-Hérault, J, Sousa, R C, Dieny, B, Nozières, J-P
• Format: Journal Article
• Language: English
• Published: IOP Publishing 20.02.2013
• Subjects: Density; Engineering Sciences; Heating; Logic; Magnetic fields; Magnetoresistive random access memory; Switching; Tantalum; Torque
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/46/7/074002

This paper is focused on thermally assisted magnetic random access memories (TA-MRAMs). It explains how the heating produced by Joule dissipation around the tunnel barrier of magnetic tunnel junctions (MTJs) can be used advantageously to assist writing in MRAMs. The main idea is to apply a heating pulse to the junction simultaneously with a magnetic field (field-induced thermally assisted (TA) switching). Since the heating current also provides a spin-transfer torque (current-induced TA switching), the magnetic field lines can be removed to increase the storage density of TA-MRAMs. Ultimately, thermally induced anisotropy reorientation (TIAR)-assisted spin-transfer torque switching can be used in MTJs with perpendicular magnetic anisotropy to obtain ultimate downsize scalability with reduced power consumption. TA writing allows extending the downsize scalability of MRAMs as it does in hard disk drive technology, but it also allows introducing new functionalities particularly useful for security applications (Match-in-Place™ technology).