Investigation of Low Temperature Magneto-Caloric, Dielectric, and Electrical Properties of Gadolinium (Gd) Modified DyMnO3

Abstract

The gadolinium (Gd) doped DyMnO₃ (Dy_0.9Gd_0.1MnO₃) was prepared by acrylamide-based gel template technique. The structural, specific heat, dielectric, electrical and magneto-dielectric properties of Dy_0.9Gd_0.1MnO₃ were investigated in this report. The XRD analysis shows characteristics peak corresponding to orthorhombic structure. The field emission scanning electron microscopy (FESEM) suggests formation of polyhedral grains with minute amount of pores. The variation of specific heat with temperature was measured at different magnetic fields. The specific heat versus temperature plot shows three distinct anomalies corresponding to T_N(Dy), T_lock and T_N(Mn). The effect of magnetic field on these transitions and magneto-caloric property of Dy_0.9Gd_0.1MnO₃ were investigated in detail. The dielectric properties of Dy₀.₉Gd₀.₁MnO₃ as functions of temperature and frequency were systematically examined. The electrical properties of the material were studied using complex impedance spectroscopy. The value of activation energy was calculated to be around 90 meV suggesting involvement of polaron in the conduction process. The magneto-dielectric response around the magnetic transition temperatures was analyzed. The magnetic field dependence of specific heat suggests its possible use in magnetic refrigeration and fuel industry at low temperature (2–50 K).