Influence of atomic roughness at the uncompensated Fe/CoO(111) interface on the exchange-bias effect
Year: 2020
Type: article
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 \ensuremath{\sim}0.35 nm, by varying layer thickness of the CoO films. It is observed that both exchange-bias field $({H}_{E})$ and coercivity $({H}_{C})$ extensively depend on the atomic scale roughness of the CoO (111) at the interface with Fe film. An opposite dependence of ${H}_{E}$ and ${H}_{C}$ 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 ${H}_{C}$ is found to be up to \ensuremath{\sim}80 K below the blocking temperature $({T}_{B})$ and the temperature dependence of ${H}_{C}$ follows the power law with a critical exponent equal to one, which indicates that, in this system, ${H}_{C}$ is more of an interface-related property than ${H}_{E}$.
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Funders: Leverhulme Trust, Department of Science and Technology, Ministry of Science and Technology, India, National Natural Science Foundation of China, Ministry of Education of the People's Republic of China, Isaac Newton Trust, Horizon 2020 Framework Programme, Engineering and Physical Sciences Research Council, Science and Engineering Research Board, National Key Research and Development Program of China
Awards: Equipment Account: Integrated Thin Film Deposition and Analysis System, G2025007194, G2985413173, G3277307869, G3345895242, G3353336042, G3598213347, G3653326389, 无稀土锰基永磁材料结构与性能研究, G4576109779, G5000197021, G504025110, G5045220161, G5200278345, Nanocomposite Oxide Thin Films For Novel Ionotronic Magnetoelectrics, G5513613107, 间隙型稀土-过渡族金属间化合物磁各向异性的调控及新型高频磁性材料研究, G6128010186, Advanced Materials Characterisation Suite in the Maxwell Centre, University of Cambridge, Precision Manufacturing of Flexible CMOS, G764977510, G7709012929, G7939624724, G8549114425, G8560042851, G8564029023, G888817064, G8953820251
OpenAlex ID: W2997828574