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Magnetic-phase transitions and magnetocaloric effects
- Source :
- Physica B-Condensed Matter, 319(1-4), 174-192. Elsevier
- Publication Year :
- 2002
- Publisher :
- Elsevier BV, 2002.
-
Abstract
- We have studied the magnetocaloric properties of a variety of compounds, like Gd5(Si1−xGex)4 with x=0.576 and 0.5875, MnFeP1−xAsx with x between 0.25 and 0.65, RTiGe with R=Tb, Dy, Ho, Er and Tm, Ni53Mn22Ga25, Mn5Si3, and Mn1.95Cr0.05Sb. These compounds have in common that they exhibit either temperature- or field-induced first-order magnetic-phase transitions. Gd5(Si1−xGex)4 exhibits simultaneously a magnetic and a structural transition, which is accompanied by a huge magnetic-entropy change. A temperature-induced ferromagnetic (FM) to paramagnetic (PM) transition and a magnetic-field-induced PM to FM transition which are both of first order are observed in MnFeP1−xAsx compounds. Here the magnetic-phase transitions are not accompanied by structural transitions. Nevertheless, a large magnetic-entropy change, comparable with that in Gd5(Si1−xGex)4, is observed in the MnFeP1−xAsx compounds. In several of the RTiGe compounds, an applied magnetic field induces an antiferromagnetic (AF) to FM phase transition. Here, we observed a magnetic anisotropy dependence of the magnetic-entropy change. The Heusler alloy Ni53Mn22Ga25 exhibits a first-order martensitic transformation accompanied by a magnetic-phase transition around 220 K. The magnitude and the shape of the magnetic-entropy changes observed for this compound are quite different. Mn5Si3 compound exhibits two successive first-order magnetic-phase transitions and shows a different type of magnetocaloric effect (MCE). Mn1.95Cr0.05Sb exhibits an AF to FM phase transition and a negative MCE. The relationship between the magnetic-phase transitions and the MCE is discussed, based on the comparison of the observed MCEs and the exchange interactions in these materials.
- Subjects :
- Phase transition
Paramagnetism
Magnetic anisotropy
Materials science
Condensed matter physics
Ferromagnetism
Diffusionless transformation
Magnetic refrigeration
Antiferromagnetism
Electrical and Electronic Engineering
Condensed Matter Physics
Electronic, Optical and Magnetic Materials
Magnetic field
Subjects
Details
- ISSN :
- 09214526
- Volume :
- 319
- Database :
- OpenAIRE
- Journal :
- Physica B: Condensed Matter
- Accession number :
- edsair.doi.dedup.....3ba910327dc7d2bde0ed80071c2829da