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Specific features of the heat capacity and thermal expansion of icosahedral holmium boride HoB50 at temperatures of 2-300 K

TitleSpecific features of the heat capacity and thermal expansion of icosahedral holmium boride HoB50 at temperatures of 2-300 K
Publication TypeJournal Article
Year of Publication2017
AuthorsNovikov, VV, Zhemoedov, NA, Matovnikov, AV, Mitroshenkov, NV, Kuznetsov, SV, Bud'ko, SL
JournalJournal of Alloys and Compounds
Volume724
Pagination782-786
Date Published11
Type of ArticleArticle
ISBN Number0925-8388
Accession NumberWOS:000407848400095
Keywordsanomalies, Antiferromagnetic, chemistry, Crystal electric field, crystal-electric-field, er, Heat capacity, ho, magnetic phase-transition, Materials Science, Metallurgical Engineering, RB50 borides, Thermal expansion, transition
Abstract

A holmium boride HoB50 polycrystalline sample was synthesised by boron-thermal reduction from the elements at high temperature. The temperature dependencies of the heat capacity C-p(T) and the unit cell parameters a(T), b(T), c(T) of holmium boride were determined experimentally in the temperature range 2-300 K. In terms of C-p(T) dependence, smooth anomalies were revealed at T-C1 max approximate to 6.5 K and T-C2 max approximate to 30 K; the first of these is caused by an antiferromagnetic transition and the second by the influence of the crystalline electric field (CEF). The high-temperature anomaly in the heat capacity of the boride is satisfactorily reproduced due to a simplified scheme for CEF-splitting of the ground state of the Ho3+ ions. The dependencies a(T), b(T), c(T) of holmium boride clearly show a pronounced anisotropy of thermal expansion. The anomalies in the temperature changes of the HoB50 unit cell volume at elevated temperatures are analysed within the CEF model described above. (C) 2017 Elsevier B.V. All rights reserved.

DOI10.1016/j.jallcom.2017.07.125
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