Influence of atomic roughness at the uncompensated Fe/CoO(111) interface on the exchange-bias effect

Rui Wu, Mingzhu Xue, Tuhin Maity, Yuxuan Peng, Samir Kumar Giri, Guang Tian, Judith L. MacManus-Driscoll, and Jinbo Yang
Phys. Rev. B 101, 014425 – Published 15 January 2020
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Abstract

The effect of interface roughness of ferromagnetic and antiferromagnetic layers on exchange bias is still not well understood. In this report we have investigated the effect of surface roughness in (111)-oriented antiferromagnetic CoO films on exchange bias with ferromagnetic Fe grown on top. The surface roughness is controlled at the atomic scale, over a range below ∼0.35 nm, by varying layer thickness of the CoO films. It is observed that both exchange-bias field (HE) and coercivity (HC) extensively depend on the atomic scale roughness of the CoO (111) at the interface with Fe film. An opposite dependence of HE and HC on interface roughness was found, which was ascribed to partially compensated spin states induced by the atomic roughness at the fully uncompensated CoO (111) surfaces and was corroborated using Monte Carlo simulations. Moreover, the onset temperature for HC is found to be up to ∼80 K below the blocking temperature (TB) and the temperature dependence of HC follows the power law with a critical exponent equal to one, which indicates that, in this system, HC is more of an interface-related property than HE.

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  • Received 26 October 2018
  • Revised 28 December 2019

DOI:https://doi.org/10.1103/PhysRevB.101.014425

©2020 American Physical Society

Physics Subject Headings (PhySH)

Condensed Matter, Materials & Applied PhysicsGeneral Physics

Authors & Affiliations

Rui Wu1,2,3,*, Mingzhu Xue1,2,*, Tuhin Maity3, Yuxuan Peng1,2, Samir Kumar Giri3, Guang Tian1,2, Judith L. MacManus-Driscoll3,†, and Jinbo Yang1,2,4,‡

  • 1State Key Laboratory for Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, People's Republic of China
  • 2Beijing Key Laboratory for Magnetoelectric Materials and Devices, Beijing 100871, People's Republic of China
  • 3Department of Materials Science and Metallurgy, University of Cambridge, Cambridge, CB3 0FS, United Kingdom
  • 4Collaborative Innovation Center of Quantum Matter, Beijing 100871, People's Republic of China

  • *These authors contributed equally to this work.
  • Corresponding author: jld35@cam.ac.uk
  • Corresponding author: jbyang@pku.edu.cn

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Issue

Vol. 101, Iss. 1 — 1 January 2020

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