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Random magnetic anisotropy in thin films of amorphous Mn sub 48 B sub 52
While crystalline MnB is a ferromagnet ({ital T}{sub {ital c}}=573 K), rf diode-sputtered thin films of composition Mn{sub 48}B{sub 52} are amorphous as ascertained by x-ray scattering and exhibit a low-field, hysteretic, static magnetization peak characteristic of a spin glass. High-field (up to 44...
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Published in: | Physical review. B, Condensed matter Condensed matter, 1989-11, Vol.40:14 |
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Main Authors: | , , |
Format: | Article |
Language: | English |
Subjects: | |
Online Access: | Get full text |
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Summary: | While crystalline MnB is a ferromagnet ({ital T}{sub {ital c}}=573 K), rf diode-sputtered thin films of composition Mn{sub 48}B{sub 52} are amorphous as ascertained by x-ray scattering and exhibit a low-field, hysteretic, static magnetization peak characteristic of a spin glass. High-field (up to 44 kG) static magnetization data at temperatures ranging between 6 and 200 K are analyzed within the random anisotropy model of Chudnovsky, Saslow, and Serota (Phys. Rev. B 33, 251 (1986)). In this model, the field-dependent magnetization at a given temperature is expressed as {ital M}({ital H})={ital M}(0)(1{minus}{ital CH}{sup {minus}1/2})+{chi}{prime}H, where the lead term follows from the analysis of a ferromagnet with a wandering axis (FWA) and the second term accounts for contributions from induced moments. The {ital T}{sup 3/2} dependence of the saturation magnetization of the FWA contribution, {ital M}(0), at low temperatures is suggestive of spin-wave excitations, while the temperature dependence of the fitting parameters {ital C} and {chi}{prime} consistently identify several characteristic temperatures associated with the magnetic behavior of {ital a}-Mn{sub 48}B{sub 52}, including the low-field spin-glass transition temperature and Curie temperature and the curvature crossover temperature (established from a classical Arrott plot) that separates the FWA state and a pseudoparamagnetic limit. |
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ISSN: | 0163-1829 1095-3795 |
DOI: | 10.1103/PhysRevB.40.9895 |