Magnetic, specific heat and powder neutron diffraction studies of Ho2In

The successive magnetic transitions and magnetic structure of hexagonal Ho2In 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)K and the magnetic order-order transition temperature 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) muB and 9.0(2) muB at 2K and 7.0(2) muB and 7.4(2) muB at 45K, respectively. The moment direction from the hexagonal c-axis is 41(10) at 2K. At 45K, 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 Tt.