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UNIVERSITY OF BUCHAREST
FACULTY OF PHYSICS Guest
2024-11-22 2:09 |
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Conference: Bucharest University Faculty of Physics 2018 Meeting
Section: Solid State Physics and Materials Science
Title:
Magneto-strictive effects via local atomic configurations in Fe-Dy and Fe-Dy-B amorphous intermetallics
Authors:
C. Locovei(1,2), A. E. Stanciu(1,2), A. Leca(1,3), N. Iacob(1), G. Schinteie(1), V. Kuncser(1)
*
Affiliation:
1) National Institute for Materials Physics, Bucharest-Magurele, Romania
2) Bucharest University, Faculty of Physics, Bucharest-Magurele, Romania
3) Politehnica University of Bucharest, Faculty of Electronics, Telecommunications and Information Technology, Bucharest, Romania
E-mail
lcvclaudiu@yahoo.com
Keywords:
magneto-strictive effects, iron, dysprosium, amorphous intermetallics,
Abstract:
The study of random magnetic anisotropy and non-collinear spin configurations in rare earth – transition metal (RE-TM) and RE-TM-B intermetallic compounds presents a special interest because their underlying mechanisms and the corresponding influence on various magnetic properties are still not fully understood. RE-TM alloys show different features depending on the ionic anisotropy of the RE element. The present work considers the investigation of magneto-strictive effects via local structure properties of amorphous RE-TM and RE-TM-B alloys, where the RE element is anisotropic (leading to a finite spin-orbit coupling). This type of structures is characterized by the fact that the random local crystal field induces modifications in the magnitude and orientation of the RE magnetic moments. The coupling of the RE and TM ions is dictated by both the RE-RE, TM-TM, RE-TM interactions and by the single ion anisotropy. In the particular case of Fe-Dy compounds (Dy being an anisotropic ion) approached within this study, the coupling is antiferromagnetic and gives rise to a sperimagnetic structure if the random single-ion anisotropy is superposed. Three samples with different Fe concentrations were prepared as ribbons by induction melting, followed by melt spinning. The exchange coupling was also varied by B addition. The structural and atomic configurations characterization was performed by X-Ray Diffraction (XRD) and Transmission Mössbauer Spectroscopy (TMS). The magneto-strictive effects were evaluated as a measure of the changes in the orientation of the average magnetic moment with respect to the sample plane, due to strains induced at different temperatures.
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