Structure and magnetic properties of TbNiAl-based deuterides

Abstract This work concerns the study of the crystal and magnetic structure of TbNiAlD x compounds ( x =0.54, 1.23 and 1.33) by neutron diffraction. TbNiAlD 0.54 is isostructural with TbNiAl. It undergoes two magnetic transitions at T 1 =16 K and T N =36 K, with magnetic structure similar to that of TbNiAl below T 1 =23 and T N =45 K. TbNiAlD 1.23 is in crystallography and magnetism comparable to TbNiAlD 1.1 . When the Tb 2 NiAl positions are occupied, an orthorhombic distortion is induced. This completely changes the magnetic ordering and could be explained by the easy magnetisation directions being perpendicular to the shortest Tb–Tb distances.