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

Abstract Within the RCo 2 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 RCo 2 compounds is TmCo 2 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 TmCo 2 , which appears together with the magnetic ordering around the critical temperature of T C ∼ 3.6 K. Poly-crystals as well as single-crystals of TmCo 2 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 ¯ m to R 3 ¯ m space group. The relation between observed magnetic and structural properties in this compound is discussed.