Crystal structure and magnetic ordering in magnetoelectric KNiPO4 investigated by means of x-ray and neutron diffraction

Abstract

The crystal structure of magnetoelectnc KNiPO4 was refined by single crystal X-ray diffraction methods at room temperature confirming orthorhombic space group Pna21. Powder neutron diffraction investigations showed that the room temperature structure is preserved down to 30 K. Consistent with magnetic susceptibility measurements, long-range antiferromagnetic ordering according to K = 0 and Shubnikov space group Pna21 is established by neutron diffraction at temperatures below TN = (25.5 ± 0.5) K. The ordered magnetic moments of (3.00 ± 0.04)μB, oriented along [1, 0, 0], indicate large orbital contributions to the magnetic moment of Ni2+. DTA studies in the temperature range from 100-1000°C, showed two phase transitions, at 486.5°C and at 581.3°C. © 1994, Copyright Taylor & Francis Group, LLC. All Rights Reserved.