Abstract
We have prepared a high quality single crystal of GdCo2B2 and studied complicated magnetism by measuring the magnetization, AC susceptibility and heat capacity. The results can be conceived in terms of low-temperature antiferromagnetism (below T-N = 22 K) undergoing three order to order magnetic phase transitions at T-1 = 18.5, T-2 = 13, and T-3 = 7K, respectively.
Measurements on the single crystal allowed us determining the weak magnetocrystalline anisotropy when the a-axis appears to be direction of the easy magnetization. In addition spin-flop transitions have been detected on magnetization loops.
We have constructed complex H-T magnetic phase diagrams and calculated magnetocaloric effect (MCE). The large magnetic entropy change of Delta S-mag((9T)) = 24 J kg(-1) K-1 is attributed to the instability of antiferromagnetic ordering which can be easily changed to field-induced ferromagnetic state.
The interpretation of experimental results is corroborated by ab initio electronic structure calculations.