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 Mn 1− x Sb x CoGe ( 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 ( T t ). 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 ⩾ 0.04 , an interesting phenomenon is appearance of single transition with ferromagnetic transition temperature ( T C ). For Mn 0.99 Sb 0.01 CoGe sample, the maximal value of the magnetic entropy change ( Δ S M ) attains about 17.7 J / kg 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.