The magnetic and magnetocaloric properties of Ni-rich Mn_0.5Fe_0.5-xNi_1+xSi_0.94Al_0.06 intermetallic system

Magnetic refrigeration is considered a viable candidate to replace the conventional vapor-gas compression refrigerators due to its high energy efficiency and environmental friendliness. The technology exploits magnetocaloric effect (MCE) exhibited by a special group of materials for its operations. MCE involves the heating and cooling of a magnetic material when exposed to an external magnetic field. A suitable material for application in this technology is desired to exhibit large MCE near room temperature and minimal thermal hysteresis loss. The intermetallic compound Mn_0.5Fe_0.5NiSi_0.94Al_0.06 has been reported to exhibit a first order phase transition and large MCE near room temperature. The first order transition in this compound is accompanied by a thermal hysteresis, which is undesirable for practical applications. In this presentation, we will discuss an experimental study performed on a series of Ni-rich Mn_0.5Fe_0.5-xNi_1+xSi_0.94Al_0.06 compounds. The goal is to explore the effects of partially replacing Fe with Ni on the structural, magnetic, and magnetocaloric properties of the materials.