FeMn Exchange Biased Storage Layer for Thermally Assisted MRAM

• Published in: IEEE transactions on magnetics Vol. 46; no. 6; pp. 2486 - 2488
• Main Authors: Gapihan, Erwan, Mackay, Ken, Nozieres, Jean-Pierre, Sousa, Ricardo C., Herault, Jeremy, Papusoi, Christian, Delaye, Marie Therese, Dieny, Bernard, Prejbeanu, I. Lucien, Ducruet, Clarisse, Portemont, Céline
• Format: Journal Article Conference Proceeding
• Language: English
• Published: New York, NY IEEE 01.06.2010; Institute of Electrical and Electronics Engineers; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Annealing; Antiferromagnetic materials; Coercive force; Cross-disciplinary physics: materials science; rheology; Current density; Density; Diffusion barriers; Electrodes; Engineering Sciences; Exact sciences and technology; Heating; Magnetic fields; Magnetic hysteresis; magnetic semiconductors; Magnetism; Magnetoresistive random access memory; Materials science; Other topics in materials science; Physics; Plasma temperature; Space vector pulse width modulation; Surface layer; Texture; Thermal barriers; Thermal stability; Writing; Magnetic hysteresis; Storage; Magnetic semiconductors; Magnetic properties
• ISSN: 0018-9464; 1941-0069
• DOI: 10.1109/TMAG.2010.2041198

Thermally assisted MRAM cells with FeMn exchange biased storage layers were successfully written using 50 ns current pulses with write power densities below 10 mW/¿m 2 and current densities below 1.3 ×10 6 A/cm 2 . These low power density values were achieved without using thermal barriers to confine the heat in the cell. Introducing thermal barriers would even further lower the write power density by increasing the heating efficiency. The storage layer coercivity increased upon anneal at 340 C. This could be related to manganese diffusion or to a texture incompatibility between the CoFe and the FeMn antiferromagnetic layer, a problem which can be fixed by insertion of appropriate diffusion barrier or texture control layer. Successful writing was observed for repeated write attempts with heating pulse power densities in the 7-12.5 mW/¿m 2 range.