Ferromagnetism at the interfaces of antiferromagnetic FeRh epilayers
The nanoscale magnetic structure of FeRh epilayers has been studied by polarized neutron reflectometry. Epitaxial films with a nominal thickness of 500 {angstrom} were grown on MgO (001) substrates via molecular-beam epitaxy and capped with 20 {angstrom} of MgO. The FeRh films show a clear transition from the antiferromagnetic (AF) state to the ferromagnetic (FM) state with increasing temperature. Surprisingly the films possess a FM moment even at a temperature 80 K below the AF-FM transition temperature of the film. We have quantified the magnitude and spatial extent of this FM moment, which is confined to within {approx}60-80 {angstrom} of the FeRh near the top and bottom interfaces. These interfacial FM layers account for the unusual effects previously observed in films with thickness <100 {angstrom}. Given the delicate energy balance between the AF and FM ground states we suggest a metastable FM state resides near to the interface within an AF matrix. The length scale over which the FM region resides is consistent with the strained regions of the film.
- Research Organization:
- Brookhaven National Laboratory (BNL) National Synchrotron Light Source
- Sponsoring Organization:
- DOE - Office Of Science
- DOE Contract Number:
- AC02-98CH10886
- OSTI ID:
- 1004627
- Report Number(s):
- BNL--94541-2011-JA; KC0401030
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 18 Vol. 82; ISSN 1098-0121; ISSN 1550-235X
- Country of Publication:
- United States
- Language:
- English
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