Exploring the microscopic origin of exchange bias with photo-electron emission microscopy (PEEM)
It is well known that magnetic exchange coupling across the ferromagnet--antiferromagnet interface results in a unidirectional magnetic anisotropy of the ferromagnetic layer, called exchange bias. Despite large experimental and theoretical efforts, the origin of exchange bias is still controversial, mainly because detection of the interfacial magnetic structure is difficult. We have applied photoelectron emission microscopy (PEEM) on several ferromagnet - antiferromagnet thin-film structures and microscopically imaged the ferromagnetic and the antiferromagnetic structure with high spatial resolution. Taking advantage of the surface sensitivity and elemental specificity of PEEM, the magnetic configuration and critical properties such as the Neel temperature were determined on LaFeO{sub 3} and NiO thin films and single crystals. On samples coated with a ferromagnetic layer, we microscopically observe exchange coupling across the interface, causing a clear correspondence of the domain structures in the adjacent ferromagnet and antiferromagnet. Field dependent measurements reveal a strong uniaxial anisotropy in individual ferromagnetic domains. A local exchange bias was observed even in not explicitly field-annealed samples, caused by interfacial uncompensated magnetic spins. These experiments provide highly desired information on the relative orientation of electron spins at the interface between ferromagnets and antiferromagnets.
- Research Organization:
- Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
- Sponsoring Organization:
- USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Materials Sciences (US)
- DOE Contract Number:
- AC03-76SF00098
- OSTI ID:
- 775145
- Report Number(s):
- LBNL-46504; LBNL/ALS-43333; R&D Project: A58128; TRN: US200305%%930
- Resource Relation:
- Conference: 8th Joint MMM-Internag Conference, San Antonio, TX (US), 01/07/2001--01/11/2001; Other Information: Supercedes report DE00775145; PBD: 22 Jan 2001;Journal of Applied Physics, Vol. 89, No. 11, pp. 7266-7268, June 1, 2001; PBD: 22 Jan 2001
- Country of Publication:
- United States
- Language:
- English
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