Magnetic and Magnetocaloric Properties of Multiferroic Oxides Gd_0.5Y_0.5MnO₃ and Eu_0.5Dy_0.5MnO₃

In this article, crystal structure, magnetism, heat capacity, magnetocaloric effect (MCE), and electrical resistivity of mixed rare-earth Gd _0.5 Y _0.5 MnO ₃ and Eu _0.5 Dy _0.5 MnO ₃ manganites have been studied. Temperature-dependent magnetization M(T) measurements suggest an antiferromagnetic order just below 6 K in Gd _0.5 Y _0.5 MnO ₃ , while no magnetic transition has been observed down to 5 K in Eu _0.5 Dy _0.5 MnO ₃ . Heat capacity data reveal anomalies at 40 and 42 K in Gd _0.5 Y _0.5 MnO ₃ and Eu _0.5 Dy _0.5 MnO ₃ , and these may correspond to Mn magnetic order as previously reported. The magnetization values are 2.8 and 3 μ _B /f.u. in 70 kOe field at 5 K for Gd _0.5 Y _0.5 MnO ₃ and Eu _0.5 Dy _0.5 MnO ₃ , respectively. MCE has been estimated in terms of isothermal magnetic entropy change (ΔS _m ) at low temperatures. The maximum values of ΔS _m are about -11 and -6.2 J kg ^-1 , respectively, for Gd _0.5 Y _0.5 MnO ₃ and Eu _0.5 Dy _0.5 MnO ₃ samples for a field change of 70 kOe at 8 K. Electrical resistivity of Gd _0.5 Y _0.5 MnO ₃ and Eu _0.5 Dy _0.5 MnO ₃ shows variable range polaron hopping behavior in the temperature range of 210-350 K.