Magnetic, specific heat and powder neutron diffraction studies of Ho22In

The successive magnetic transitions and magnetic structure of hexagonal Ho22In 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 Tc=85.0(2)Tc=85.0(2) K and the magnetic order–order transition temperature Tt=32.5(2)Tt=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) μBμB and 9.0(2) μBμB at 2 K and 7.0(2) μBμB and 7.4(2) μBμB at 45 K, respectively. The moment direction from the hexagonal cc-axis is 41(10)∘41(10)∘ at 2 K. At 45 K, the reliability factor takes so shallow minimum at around 26(20)∘26(20)∘ that one cannot exclude the alignment of moments along the cc-axis in the higher temperature phase. A model is suggested for the magnetic structure change at TtTt.