Magnetic structures of non-stoichiometric hexagonal RNi1-xIn1+x (R=Dy, Ho, Er) compounds

Results of neutron diffraction studies of DyNi0.9In1.1, HoNi0.8In1.2 and ErNi0.9In1.1 compounds crystallizing in the hexagonal ZrNiAl-type structure are reported. Previously published data for stoichiometric 1-1-1 compounds indicate that HoNiIn and ErNiIn compounds are ferromagnets (ordering along the c-axis) with TC of 22 and 9 K, respectively, while DyNiIn was found to be an antiferromagnet with TN of 32 K (J. Magn. Magn. Mater. 262 (2003) L177; J. Magn. Magn. Mater., in press). DC bulk magnetic measurements show that with the rise of the x parameter the ordering temperature is lowered; moreover changes in the magnetic ordering occur. At 1.5 K the HoNi0.8In1.2 compound has a non-collinear magnetic structure, for the ErNi0.9In1.1 compound an additional sine-modulated component lying in the basal plane was found. For the DyNi0.9In1.1 compound the antiferromagnetic character of magnetic coupling is conserved, but some changes in comparison to 1-1-1 stoichiometry were noticed