Effect of L1{sub 2} ordering in antiferromagnetic Ir-Mn epitaxial layer on exchange bias of FePd films
- Department of Materials Science and Engineering, Feng Chia University, Taichung 407, Taiwan (China)
- National Synchrotron Radiation Research Center, Hsinchu 300, Taiwan (China)
- Department of Power Mechanical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan (China)
Two series of samples of single-layer IrMn and IrMn/FePd bilayer films, deposited on a single-crystal MgO substrate at different IrMn deposition temperatures (T{sub s} = 300–700 °C), were investigated using magnetron sputtering. L1{sub 2} ordering was revealed for the 30 nm-thick IrMn epitaxial (001) films with T{sub s} ≥ 400 °C, determined by synchrotron radiation x-ray diffractometry (XRD). XRD results also provide evidence of the epitaxial growth of the IrMn films on MgO substrate. Increasing T{sub s} from 400 to 700 °C monotonically increases the ordering parameter of L1{sub 2} phases from 0.17 to 0.81. An in-plane exchange bias field (H{sub eb}) of 22 Oe is obtained in a 10 nm-thick FePd film that is deposited on the disordered IrMn films. As the L1{sub 2} ordering of the IrMn layers increases, the H{sub eb} gradually decreases to 0 Oe, meaning that the exchange bias behavior vanishes. The increased surface roughness, revealed by atomic force microscopy, of the epitaxial IrMn layers with increasing T{sub s} cannot be the main cause of the decrease in H{sub eb} due to the compensated surface spins regardless of the disordered and ordered (001) IrMn layers. The change of antiferromagnetic structure from the A1 to the L1{sub 2} phase was correlated with the evolution of H{sub eb}.
- OSTI ID:
- 22410076
- Journal Information:
- Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 17 Vol. 117; ISSN JAPIAU; ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANTIFERROMAGNETISM
ATOMIC FORCE MICROSCOPY
DEPOSITION
EPITAXY
FILMS
INTERMETALLIC COMPOUNDS
IRIDIUM
LAYERS
MAGNESIUM OXIDES
MANGANESE
MONOCRYSTALS
ROUGHNESS
SPUTTERING
SUBSTRATES
SURFACES
SYNCHROTRON RADIATION
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION