Magnetic, specific heat and powder neutron diffraction studies of Ho [formula omitted]In

Abstract

The successive magnetic transitions and magnetic structure of hexagonal Ho 2 In compound have been investigated by the magnetic, specific heat and powder X-ray and neutron diffraction measurements. Two magnetic phase transitions have been observed at the paramagnetic to ferromagnetic transition temperature T c = 85.0 ( 2 ) K and the magnetic order–order transition temperature T t = 32.5 ( 2 ) K. No antiferromagnetic reflections have been observed in the neutron diffraction patterns. The Rietveld analysis has indicated that the Ho atoms possess different moment values at two inequivalent sites: 8.8(2) μ B and 9.0(2) μ B at 2 K and 7.0(2) μ B and 7.4(2) μ B at 45 K, respectively. The moment direction from the hexagonal c -axis is 41 ( 10 ) ∘ at 2 K. At 45 K, the reliability factor takes so shallow minimum at around 26 ( 20 ) ∘ that one cannot exclude the alignment of moments along the c -axis in the higher temperature phase. A model is suggested for the magnetic structure change at T t .