Structure sensitivity of magnetization processes at the spin-reorientation transition in ND2Fe14B

• Published in: Journal of applied physics 1991-04, Vol.69 (8), p.5562-5564
• Main Authors: FOLDEAKI, M, KOSZEGI, L, DUNLAP, R. A
• Format: Article
• Language: English
• Subjects: Applied sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Magnetic properties and materials; Magnetically ordered materials: other intrinsic properties; Metals. Metallurgy; Physics; Saturation moments and magnetic susceptibilities
• ISSN: 0021-8979; 1089-7550
• DOI: 10.1063/1.347950

Calculations based on different micromagnetic models were carried out in order to describe the behavior of the ac susceptibiIity in the temperature range of the spin-reorientation transitions in hard magnets. It was found that the rotational susceptibility shows a sharp cusp at the transition temperature, while the contribution due to an increase in the domain- wall mobility is less significant. As well, there is a significant contribution of domain- wall processes to the overall susceptibility over the entire range of temperatures studied (80– 180 K). For randomly oriented bulk samples, the susceptibility cusp has been experimentally observed. The susceptibility of randomly oriented powders shows only a moderate temperature dependence below the transition, followed by a sharp decrease at the transition temperature. The frequency dependence of the susceptibility showed the behavior expected for conducting samples, proving that domain-wall dynamics (e.g., aftereffects, lattice-defect–domain-wall interactions, etc.) do not play a role in the observed temperature dependence of the susceptibility.