Magnetic response of FeF{sub 2} films on (100) MgO (abstract)
- Argonne National Laboratory, Argonne, Illinois 60439 (United States)
- Physics Department 0319, University of California--San Diego, La Jolla, California 92093 (United States)
Pairs of FeF{sub 2}/Fe films show large exchange bias. In bulk FeF{sub 2} is antiferromagnetically ordered below 78 K, and the magnetic moments of the corner and center atoms in the rutile structure are respectively parallel and antiparallel to the tetragonal axis. A polarized neutron reflection measurement was taken on a single film of FeF{sub 2}, 920 {Angstrom} thick, grown in the (110) orientation on a MgO (100) face. In polarized neutron reflection is measured the polarization dependence of the reflectivity as a function of k{sub z}, the component of the neutron momentum perpendicular to the surface. From this, in principle, the detailed net magnetization profile along the thickness of the film can be obtained. Reflectivity patterns taken with the sample in different physical conditions (temperatures: 4.2{endash}120 K, magnetic fields: 100{endash}5000 Oe) showed the interference pattern characteristic for a 920 {Angstrom} thick film. However the polarization dependence of the reflectivity was in all cases very weak and only by repeated runs it was possible to observe a statistically significant difference between patterns obtained at 80 K in field of 5 kOe and at 4.2 K after field cooling in the same field. In the paramagnetic region no polarization was observed; in the antiferromagnetic region weak polarization peaks were found at the values of k{sub z} corresponding to minima of the interference oscillations. The precision of the measurements does not allow to give yet a detailed depth profile of the net magnetization. While the presence of a strong ferromagnetic component close to the surface seems to be ruled out, the results can be fitted by a magnetization of 0.025 {mu}{sub B}/Fe uniform throughout the film as well as by the presence of 1{mu}{sub B}/Fe on the three atomic planes most adjacent to MgO. {copyright} {ital 1997 American Institute of Physics.}
- DOE Contract Number:
- W-31-109-ENG-38
- OSTI ID:
- 554276
- Report Number(s):
- CONF-961141-; ISSN 0021-8979; TRN: 98:000883
- Journal Information:
- Journal of Applied Physics, Vol. 81, Issue 8; Conference: 41. annual conference on magnetism and magnetic materials, Atlanta, GA (United States), 12-15 Nov 1996; Other Information: PBD: Apr 1997
- Country of Publication:
- United States
- Language:
- English
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