M{umlt o}ssbauer study of permanent-magnet R{sub 2}Fe{sub 17{minus}{ital x}}M{sub {ital x}}C{sub {ital y}} compounds
- Behlen Laboratory of Physics and Center for Materials Research and Analysis, University of Nebraska, Lincoln, Nebraska 68588-0111 (United States)
- Department of Physics and Astronomy, University of Delaware, Newark, Delaware 19716 (United States)
We report Fe{sup 57} M{umlt o}ssbauer spectroscopy studies of the effect of carbon doping on the magnetic properties of the Fe sites of R{sub 2}Fe{sub 17{minus}{ital x}}M{sub {ital x}}C{sub {ital y}}, and of the presence of multiple phases in these systems. In this study two systems, Sm{sub 2}Fe{sub 14}Al{sub 3}C{sub {ital y}}, where {ital y}=0, 1.0, 2.0, and 3.0, and Nd{sub 2}Fe{sub 14.54}Si{sub 2.46}C{sub {ital y}}, where {ital y}=0, 0.432, and 2.544, were measured at room temperature and analyzed. The ternary compounds R{sub 2}Fe{sub 17{minus}{ital x}}M{sub {ital x}}C{sub {ital y}} studied here have the rhombohedral Th{sub 2}Zn{sub 17} structure with {ital c}-axis anisotropy. The Al and Si site occupation used in the fitting were taken from previous results. Analysis of the M{umlt o}ssbauer spectra showed that the hyperfine fields for the different sites decreased in the order 6{ital c}, 9{ital d}, 18{ital f}, and 18{ital h}. The average hyperfine field for Sm{sub 2}Fe{sub 14}Al{sub 3}C{sub {ital y}} was found to increase with increasing carbon concentration, which is in qualitative agreement with magnetic measurements. For Nd{sub 2}Fe{sub 14.54}Si{sub 2.46}C{sub {ital y}} the average hyperfine field was found to increase for low C concentration and decrease for high C concentration; this behavior is in agreement with our magnetization measurements. The measured average isomer shift relative to {alpha}-iron was found to increase with {ital y}. In these compounds alloying with C and/or M can improve the magnetic properties such as Curie temperature and magnetization which make them potential candidates for permanent magnet development. {copyright} {ital 1996 American Institute of Physics.}
- OSTI ID:
- 280000
- Report Number(s):
- CONF-951101-; ISSN 0021-8979; TRN: 9608M0051
- Journal Information:
- Journal of Applied Physics, Vol. 79, Issue 8; Conference: 40. conference on magnetism and magnetic materials, Philadelphia, PA (United States), 6-9 Nov 1995; Other Information: PBD: Apr 1996
- Country of Publication:
- United States
- Language:
- English
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