MULTISTEP MAGNETIZATION OF SINGLE-CRYSTAL TBNISN AND DYNISN IN HIGH FIELDS

Magnetic and transport properties are reported on TbNiSn and DyNiSn si ngle crystals with the orthorhombic TiNiSi-type structure. Thermal var iation of the electrical resistivity and magnetic susceptibility indic ates the existence of three successive magnetic transitions at T1 = 6. 0 K, T2 = 7.6 K and T(N) = 18.5 K in TbNiSn and two magnetic transitio ns at T1 = 5.4 K and T(N) = 7.3 K in DyNiSn. Magnetization up to 15 T along the b-axis at 1.6 K exhibits a four-step metamagnetic transition for TbNiSn and a three-step one for DyNiSn. High-field magnetization curves for TbNiSn in fields up to 30 T at 1.4 K show unexpected small jumps, which may suggest a switching of the magnetic axis.