Fundamental magnetic properties have been studied in RFexAl12-x (R - heavy rare-earth element) compounds with the tetragonal crystal structure of the ThMn12 type. In the homogeneity range 4 ≤ x ≤ 6, exchange interactions and magnetocrystalline anisotropy of the Fe sublattice are significantly modified as found in LuFexAl12-x with non-magnetic Lu. With increasing Fe content, antiferromagnetic exchange interactions weaken and ferromagnetic strengthen. The change of the type of magnetic ordering occurs in the vicinity of x = 5. The Fe sublattice displays an easy-plane magnetic anisotropy that weakens with growing Fe concentration. RFe5Al7 compounds with magnetic R are highly anisotropic ferrimagnets with Curie temperatures from 193 to 262 K. Spontaneous and field-induced magnetic phase transitions of anisotropic and exchange nature have been found in RFe5Al7 by measurements of magnetization and sound propagation. The transitions provide quantitative information on the R-Fe inter-sublattice exchange. A correlation between the R element and the fundamental magnetic properties has been found for RFe5Al7. The Fe magnetic moment is near 8 µB per formula unit. The compounds with R - Tb, Dy, Ho and Er have a compensation of the rare- earth and iron sublattice magnetizations. The compensation point and Curie...
| Identifer | oai:union.ndltd.org:nusl.cz/oai:invenio.nusl.cz:332311 |
| Date | January 2014 |
| Creators | Gorbunov, Denis |
| Contributors | Andreev, Alexander, Kamarád, Jiří, Svoboda, Pavel |
| Source Sets | Czech ETDs |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/doctoralThesis |
| Rights | info:eu-repo/semantics/restrictedAccess |
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