Exploring magnetocaloric and heat capacity behavior in Fe doped Mn5Ge3 alloy.

Magnetocaloric properties of hexagonally structured Mn 5 − x Fe x Ge 3 (x = 0.15 , 0.3, and 0.5) alloys have been investigated using DC magnetization and heat capacity measurements. The maxima of entropy change, − Δ S m max ∼ 5.04 (5.57) J/kg K, along with an adiabatic temperature change of Δ T a d max ∼ 5.05 (7.25) K was observed for x = 0.15 (0.5) at an applied magnetic field H = 5 T. With the scaling analysis of − Δ S m , the rescaled curves collapse onto a single universal curve anticipated by the mean-field theory, revealing a second-order type of magnetic transition. Furthermore, − Δ S m max follows a power law of H n with n = 0.597 (3) , 0.591(3), and 0.586(3) for Mn 5 − x Fe x Ge 3 (x = 0.15 , 0.3, and 0.5) alloys, respectively. The refrigerant capacity (RC) is increased from 400 J/kg (for x = 0.15) to 420 J/kg (for x = 0.5) with Fe doping in Mn 5 Ge 3. Moreover, the coefficient of refrigerant performance (CRP) enhances with Fe doping from 0.06 (for x = 0.15) to 0.1 (for x = 0.5). Thus, high RC and reasonable CRP values for earth-abundant Mn-based Mn–Fe–Ge alloys promise the potential to replace the high-cost rare-earth (Gd) and heavy metal-based metallic magnetocaloric systems for use in environment-friendly magnetic refrigeration technology. [ABSTRACT FROM AUTHOR]