Magnetic properties of ErRh3B2 and of some related Rare Earth Transition Metal Borides
Jonte BERNHARD
Department of Electrical Engineering, School of Engineering, Falun/Borlänge University, S78110 Borlänge, Sweden.
The ternary systems RERhB (RE = Rare earth elements) have attracted much interest because of the occurrence of reentrant superconductivity and coexistence of ferromagnetism and superconductivity in ErRh4B4 and because of unusual magnetic properties in the RERh3B2 system.
The compounds of the ternary composition RERh3B2 crystallize either in the hexagonal CeCo3B2 type structure (RE = La Gd) or in the ErIr3B2 type structure (RE = Tb Lu), the latter being a base-centered monoclinic structure with space group C2/m. The CeCo3B2 structure (P6/mmm) is derived from the binary CaCu5 type structure (P6/mmm) and the ErIr3B2 type structure is a distortion variant of the CeCo3B2 structure. The crystal structure of ErRh3B2 belongs to the monoclinic system with a crystal lattice of ErIr3B2 type. Recent X-ray studies show that the structure is more complex.
The ternary system ErRh3B2 is known to be ferromagnetic. Recent magnetization measurements and neutron diffraction measurements show however a more complicated picture. The highly anisotropic magnetic properties of ErRh3B2 will be described and compared with the properties exhibited by other ternary compounds in the RERh3B2 system.