Spin-torque ferromagnetic resonance measurements utilizing spin Hall magnetoresistance in W/Co40Fe40B20/MgO structures

Congli He, Aryan Navabi, Qiming Shao, Guoqiang Yu, Di Wu, Weihua Zhu, Cheng Zheng, Xiang Li, Qing Lin He, Seyed Armin Razavi, Kin L. Wong, Zongzhi Zhang, Pedram Khalili Amiri, Kang L. Wang

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

We study the magnetic properties of W/Co40Fe40B20 (CoFeB)/MgO films using the spin-torque ferromagnetic resonance (ST-FMR) technique. This study takes the advantage of the spin Hall magnetoresistance (SMR) for generating an oscillating resistance, which is one of the necessary requirements for obtaining mixing voltage in the ST-FMR technique. We have measured both the as-grown and the annealed samples with different CoFeB layer thicknesses, which include the in-plane and out-of-plane magnetic anisotropies. The spectra for these two types of anisotropies show distinct signatures. By analyzing the ST-FMR spectra, we extract the effective anisotropy field for both types of samples. In addition, we investigate the influence of CoFeB thickness and annealing on the Gilbert damping constant. Our experiments show that by taking advantage of SMR, the ST-FMR measurement acts as an effective tool with high sensitivity for studying the magnetic properties of ultrathin magnetic films.

Original languageEnglish (US)
Article number202404
JournalApplied Physics Letters
Volume109
Issue number20
DOIs
StatePublished - Nov 14 2016

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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