Anisotropy and magnetic phase transitions in the rare earth tetraborides TbB4, HoB4 and ErB4☆

Abstract In order to determine the electronic properties of the rare earth tetraborides TbB 4 , HoB 4 and ErB 4 (UB 4 structure type) large single crystals of 50–100 mg were prepared by the Czochralski and the aluminium flux methods. Magnetic and electrical measurements were performed at temperatures ranging from 2 to 300 K and under magnetic fields up to 80 kOe, applied along various crystallographic directions. All these tetraborides are metallic, and they show long-range antiferromagnetic ordering at low temperatures under a weak field. However, their detailed magnetic structure and field-temperature phase diagrams, confirmed by neutron diffraction experiments, are quite different.