The structural and magnetic properties of as-cast Mn1-xAlxCoGe (0 ≤ x ≤ 0.05) have been studied by X-ray diffraction, differential scanning calorimetry, and magnetization measurements. The partial substitution of Al for Mn in Mn1-xAlxCoGe results in a decrease in the martensitic transition temperature TM. For the concentration range 0 ≤ x ≤ 0.01, TM was found to coincide with ferromagnetic transition temperature (TC) resulting in a first-order magnetostructural transition (MST). A further increase in aluminum concentration resulted in a splitting of the phase transition temperatures, which included a drastic decrease in the martensitic temperature. The compounds with x > 0.02 showed a single transition at TC. The maximum values of the magnetic entropy changes (-ΔSM) were ∼18 J/kgK, 12 J/kgK, and 7 J/kgK for ΔH = 5T at 313 K (x = 0.00), 286 K (x = 0.01), and 220 K (x = 0.02), respectively. The maximum value of the relative cooling power (RCP) was found to be 303 J/kg for x = 0.01 at T = 286 K for ΔH = 5T. It has been established that as-cast samples of this system show large value of MCE near room temperature making this system a promising material for magnetic cooling technologies.
Publication Source (Journal or Book title)
Journal of Alloys and Compounds
Aryal, A., Quetz, A., Pandey, S., Samanta, T., Dubenko, I., Hill, M., Mazumdar, D., Stadler, S., & Ali, N. (2017). Magnetostructural phase transitions and magnetocaloric effects in as-cast Mn1-xAlxCoGe compounds. Journal of Alloys and Compounds, 709, 142-146. https://doi.org/10.1016/j.jallcom.2017.03.149