Angle range of vanished coercivity controlled by cooling field and interfacial coupling in exchange-biased systems
Department of Physics, College of Sciences, Northeastern University, 110819, Shenyang, China
2 State Key Laboratory of Rolling and Automation, Northeastern University, 110819, Shenyang, China
Accepted: 18 July 2022
Published online: 1 August 2022
In the field of magnetic data storage, it is beneficial to provide a read out signal separately so that each function can be optimized independently. Thus it is desired that the magnetic hysteresis loop is completely displaced to one side of the origin and the loop shift, i.e., exchange bias, is controllable. We report a numerical study on the angular dependencies of exchange bias and coercivity at low temperature after field cooling in ferromagnet/antiferromagnet bilayers with ideally uniaxial magnetocrystalline anisotropies, based on Monte-Carlo simulation. When the external magnetic field is noncollinear with the anisotropy axis meanwhile the temperature is lower than a critical value, exchange bias may emerge while coercivity may completely vanish. Moreover, the influences of cooling field and interfacial exchange coupling on the range of angle between external magnetic field and anisotropy axis where coercivity vanishes are discussed. The results show that the upper and lower limits of angle range depend on cooling field and interfacial exchange coupling, respectively. A high cooling field and a large interfacial exchange coupling induce the ferromagnetic magnetization strongly coupled to a large net magnetization in the antiferromagnetic layer, which widens the angle range of vanished coercivity. This work proposes a flexible method access to a mode of full exchange bias with no coercivity simply through tilting the magnetic field with respect to the anisotropy axis at low temperature.
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