Free- and reference-layer magnetization modes versus in-plane magnetic field in a magnetic tunnel junction with perpendicular magnetic easy axis

Hamid Mazraati, Tuan Q. Le, Ahmad A. Awad, Sunjae Chung, Eriko Hirayama, Shoji Ikeda, Fumihiro Matsukura, Hideo Ohno, and Johan Åkerman

Phys. Rev. B 94, 104428 – Published 26 September 2016

Abstract

We study the magnetodynamic modes of a magnetic tunnel junction with perpendicular magnetic easy axis (p-MTJ) in in-plane magnetic fields using device-level ferromagnetic resonance spectroscopy. We compare our experimental results to those of micromagnetic simulations of the entire p-MTJ. Using an iterative approach to determine the material parameters that best fit our experiment, we find excellent agreement between experiments and simulations in both the static magnetoresistance and magnetodynamics in the free and reference layers. From the micromagnetic simulations, we determine the spatial mode profiles, the localization of the modes and, as a consequence, their distribution in the frequency domain due to the inhomogeneous internal field distribution inside the p-MTJ under different applied field regimes. We also conclude that the excitation mechanism is a combination of the microwave voltage modulated perpendicular magnetic anisotropy, the microwave Oersted field, and the spin-transfer torque generated by the microwave current.

Received 8 April 2016
Revised 21 July 2016

DOI:https://doi.org/10.1103/PhysRevB.94.104428

Physics Subject Headings (PhySH)

Magnetic anisotropy Spintronics

Magnetic tunnel junctions

Condensed Matter, Materials & Applied Physics

Authors & Affiliations

Hamid Mazraati^1,2, Tuan Q. Le², Ahmad A. Awad^1,3, Sunjae Chung^2,3, Eriko Hirayama⁴, Shoji Ikeda^4,5,6, Fumihiro Matsukura^4,5,7, Hideo Ohno^4,5,6,7, and Johan Åkerman^1,2,3

¹NanOsc AB, SE-Kista 164 40, Sweden
²Department of Materials and Nanophysics, School of Information and Communication Technology, KTH Royal Institute of Technology, Electrum 229, SE-16440 Kista, Sweden
³Department of Physics, University of Gothenburg, SE-412 96, Gothenburg, Sweden
⁴Laboratory for Nanoelectronics and Spintronics, Research Institute of Electrical Communication, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
⁵Center for Spintronics Integrated Systems, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan
⁶Center for Innovative Integrated Electronic Systems, Tohoku University, 468-1 Aramaki Aza Aoba, Aoba-ku, Sendai 980-0845, Japan
⁷WPI Advanced Institute for Materials Research, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan

Article Text (Subscription Required)

Click to Expand

References (Subscription Required)

Click to Expand

Issue

Vol. 94, Iss. 10 — 1 September 2016

Reuse & Permissions

Access Options

Author publication services for translation and copyediting assistance advertisement

Physical Review B

covering condensed matter and materials physics