Magnetic properties and magnetocaloric effect in Ho6-xErxMnBi2 compounds

Magnetic properties and magnetocaloric effect of compounds Ho6-xErxMnBi2 (x=0,3,6) are investigated experimentally. All the compounds crystallize in the hexagonal Zr6CoAs2-type structure and show a sharp drop in the magnetization around their respective magnetic ordering temperature, which is 201 K (x=0), 147 K (x=3), and 98 K (x=6), respectively. Either thermal or magnetic hysteresis around the phase transition is not observed, suggesting a second order phase transition nature. The magnetic entropy change (ΔSm) calculated from the Maxwell relation using the collected magnetization data is 10.6 (x=6), 7.3 (x=3), and 5.0 J kg-1 K-1 (x=0), respectively. The shape of the ΔSm-T curve has a good symmetry below and above the magnetic ordering temperature, and the value of the magnetic entropy change increases monotonously with increasing field change. The calorimetric technique has also been used for Er6MnBi2 to check the credibility of the magnetic method.