The effect of Sb doping for Mn on structure, magnetic properties and magnetocaloric effect of Mn1−xSbxCoGe alloys

The effect of Sb doping on the structure, magnetic properties and magnetocaloric effect of Mn1−xSbxCoGe (x = 0, 0.01, 0.02, 0.04, 0.06) alloys have been investigated. The doping of Sb for Mn results in the decrease of the structural transition temperature (Tt). For compound with x ≤ 0.01, the coupling of the magnetic and structural transitions occurs, leading to so called first-order magnetostructural transition (MST). Continually increasing x to 0.02 leads to decoupling of the magnetic and structural transitions. For \(x \geqslant 0.04\), an interesting phenomenon is appearance of single transition with ferromagnetic transition temperature (TC). For Mn0.99Sb0.01CoGe sample, the maximal value of the magnetic entropy change \((\left| {\Delta {S_{\text{M}}}} \right|)\) attains about \(17.7\,{\text{J}}/{\text{kg}}\,{\text{K}}\), and the refrigerant capacity (RC) can reach about 204 J/kg under a field change of 5 T. The small magnetic hysteresis, and large RC with MST near room temperature would make this alloy system prospectively put into use for room-temperature magnetic refrigeration materials.