Magnetic structure of TbNiSn single crystals

Measurements of magnetization and neutron diffraction have been performed on TbNiSn single crystals with an orthorhombic (Pnma) TiNiSi-type structure. Magnetic measurements indicate that this compound exhibits the four successive magnetic phase transitions at T-1 = 2.0 K, T-2 = 6.0 K, T-3 = 7.6 K and T-N = 18.5 K. There is little difference in neutron diffraction patterns between above and below T-1. The magnetic structure is of a square-wave with Q = (0.600, 0.345, 0) for T < T-2, Q = (0.665, 0.33, 0) for T-2 < T < T-3 and of a sine-modulated type with Q = (0.685, 0.33, 0) for T-3 < T < T-N.