UH.sub.3./sub.-based ferromagnets: new look at an old material

0458912 - FZÚ 2017 RIV NL eng J - Journal Article
Havela, L. - Paukov, M. - Tkach, I. - Matěj, Z. - Kriegner, D. - Mašková, S. - Vondráčková, B. - Prachařová, M. - Turek, I. - Diviš, M. - Cieslar, M. - Drozdenko, D. - Kim-Ngan, N.-T.H. - Andreev, Alexander V.
UH₃-based ferromagnets: new look at an old material.
Journal of Magnetism and Magnetic Materials. Roč. 400, Feb (2016), 130-136. ISSN 0304-8853. E-ISSN 1873-4766
Institutional support: RVO:68378271
Keywords : uranium * hydride * ferromagnetism * coercivity * magnetostriction
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.630, year: 2016

UH3 is the first discovered ferromagnet purely based on 5f electronic states. Although the U metal is Pauli paramagnet, reduced 5f-5f overlap in compounds allows for moment formation and ordering. The stable form beta-UH3, has its high TC = 165 K. Properties of metastable alpha-UH3 with could be never well established. We attempted to synthesize alpha phase starting from the gamma-U alloys. While up to 15% Zr a contamination by beta-phase was obtained, 20% Zr yielded single alpha phase. The TC value remains high and very similar to that of beta phase. It is an increase up to 187 K for 15% Zr followed by a weak decrease. Magnetic moments remain close to 1 mB/U atom. The 5f magnetism exhibits a high coercivity (up to 5.5 T) and large spontaneous volume magnetostriction 0.0032. Even higher increase of TC, reaching up to 203 K, can be achieved in analogous Mo stabilized hydrides, which yield an amorphous structure.

Permanent Link: http://hdl.handle.net/11104/0259124