Asymmetric Magnetization Switching in Perpendicular Magnetic Tunnel Junctions: Role of the Synthetic Antiferromagnet's Fringe Field

Asymmetric Magnetization Switching in Perpendicular Magnetic Tunnel Junctions: Role of the Synthetic Antiferromagnet’s Fringe Field

M. Lavanant, P. Vallobra, S. Petit Watelot, V. Lomakin, A.D. Kent, J. Sun, and S. Mangin

Phys. Rev. Applied 11, 034058 – Published 25 March 2019

Abstract

The field- and current-induced magnetization reversal of a $Co$ - $Fe$ - $B$ layer in a perpendicular magnetic tunnel junction (pMTJ) is studied at room temperature. The magnetization switching probability from the parallel (P) state to the antiparallel (AP) state and from AP to P is found to be asymmetric. We observe that this asymmetry depends on the magnetic configuration of the synthetic antiferromagnetic (SAF). The state diagram and the energy landscape are compared for two SAF configurations. We conclude that the asymmetry is due to the inhomogeneity of the fringe field generated by the SAF. Our study highlights the role of the reference-layer fringe field on the free layer’s energy barrier height, which has to be carefully controlled for memory applications.

Received 19 September 2018
Revised 21 December 2018

DOI:https://doi.org/10.1103/PhysRevApplied.11.034058

Physics Subject Headings (PhySH)

Magnetic anisotropy Magnetic interactions Magnetization switching Spin transfer torque Spintronics

Antiferromagnets Magnetic tunnel junctions Nanostructures

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

M. Lavanant¹, P. Vallobra¹, S. Petit Watelot¹, V. Lomakin², A.D. Kent³, J. Sun⁴, and S. Mangin^1,*

¹Institut Jean Lamour, CNRS-UMR 7198, Université de Lorraine, 2, allée Guinier, F-5400 Nancy, France
²Center for Memory and Recording Research, University of California San Diego, 9500 Gilman Dr., La Jolla, California 92093-0401, USA
³Center for Quantum Phenomena, Department of Physics, New York University, 726 Broadway, New York, New York 10003, USA
⁴IBM T.J. Watson Research Center, IBM, 1101 Kitchawan Rd, Rt 13 Yorktown Heights, New York 10598, USA