Effect of Al Substitution on Structural, Magnetic, and Magnetocaloric Properties of Er6Fe23-xAlx (x=0 and 3) Intermetallic Compounds

The structural, magnetic, and magnetocaloric properties of Er6Fe23-xAlx (x = 0 and 3) intermetallic compounds have been studied systematically. Samples were prepared using the arc furnace by annealing at 1073 K for one week. Rietveld analysis of XRD shows the formation of pure crystalline phase with cubic Fm-3m structure. Refinement results show that the unit cell volume decreases with increasing Al content. The Curie temperature Tc of the prepared samples was found to be strongly dependent on the aluminum content. This reduces magnetization and the ferrimagnetic phase transition temperature (Tc) from 481 K (for x = 0) to 380 K (for x = 3), is due to the substitution of magnetic element (Fe) by non-magnetic atoms (Al). With the increase of the Al content, a decrease in the values of magnetic entropy is observed. The magnitude of the isothermal magnetic entropy (|SM|) at the Tc decreases from 1.8 J/kg.K for x = 0 to 0.58 J/kg.K for x = 3 for a field change 14 kOe. Respectively, the relative cooling power (RCP) decreases with increasing Al content reaching 42 Jkg(-1) for x = 0 to 28 Jkg(-1) for x = 3.