The effect of single crystalline substrates and ion-beam bombardment on exchange bias in nanocrystalline NiO/Ni80Fe20 bilayers

Authors

D L. Cortie, University of WollongongFollow
C Shueh, National Chung Hsing University, Taichung
B-C Lai, National Chung Hsing University, Taichung
P W. T Pong, University of Hong Kong
J van Lierop, University of Manitoba
F Klose, ANSTOFollow
K-W Lin, National Chung Hsing University, Taichung

RIS ID

87656

Publication Details

Cortie, D. L., Shueh, C., Lai, B., Pong, P. W. T., Lierop, J. van., Klose, F. & Lin, K. (2014). The effect of single crystalline substrates and ion-beam bombardment on exchange bias in nanocrystalline NiO/Ni80Fe20 bilayers. IEEE Transactions on Magnetics, 50 (1),

Abstract

Methods to modify the magnetic coercivity and exchange bias field of nanocrystalline antiferromagnetic/ferromagnetic NiO/Ni80Fe20 thin films were investigated for bilayers grown using ion-assisted deposition onto different single crystalline substrates. An enhanced coercivity was found at 298 K for the films deposited on single crystalline MgO (100) and Al2O3 (11-20) substrates. After field cooling the films to 50 K, the NiO/NiFe bilayer grown on Al2O3 (11-20) exhibited the largest exchange bias ( - 25 Oe). The second part of the study investigated ion-beam modification of the ferromagnetic surface prior to the deposition of the NiO layer. A range of ion-beam bombardment energies (VEH) were used to modify in situ the NiFe surface during the deposition of NiO/NiFe/SiO2 films. Cross-sectional transmission electron microscopy showed a systematic reduction in the thickness of the NiFe layers with increasing Ar+ bombardment energies attributed to etching of the surface. In addition, the bombardment procedure modified the magnetic exchange bias of the composite structure in both the as-prepared and field-cooled state.