Lattice distortion in TmCo2: A poly- and single-crystal study

摘要

Within the RCo2 family of compounds, a structural distortion linked with the onset of magnetic ordering around the critical temperature can be observed. One of the less explored RCo2 compounds is TmCo2 probably due to its low Curie temperature. Exceptionally this compound, given its position at the end of the ferrimagnetic series, shows discrepancies in the ordering of the Co sub-lattice because of a weak Weiss molecular field. In this paper we focus on the structural distortion in TmCo2, which appears together with the magnetic ordering around the critical temperature of T-c similar to 3.6 K. Poly-crystals as well as single-crystals of TmCo2 were used in our experiments. For both kinds of samples we observed the same type of the rhombohedral distortion along the [111] direction from the cubic Fd (3) over barm to R (3) over barm space group. The relation between observed magnetic and structural properties in this compound is discussed. (C) 2018 Elsevier B.V. All rights reserved.