Magnetic structure of Tb2CuIn3

Abstract The intermetallic compound Tb 2 CuIn 3 has been studied by means of neutron diffraction at various temperatures ranging from 293 to 3.8 K. Data analysis of the high temperature region confirms the hexagonal crystal structure (space group P6/mmm ) with Tb at 1a, Cu and In statistically distributed at 2d positions. The unit cell constants are a =4.702(1) A and c =3.682(2) A. Below 33 K, Tb 2 CuIn 3 undergoes a magnetic phase transition into a collinear antiferromagnetic structure described in an orthorhombic unit cell with A = a , B = a √3, C = c . Terbium magnetic moments of 6.8 μ B at 3.8 K are oriented along the c axis. Complementary susceptibility measurements confirm the transition temperature. The magnetic isotherm at 5 K in fields with μ o H up to 7 T is far from saturation.