Double magnetic phase transitions and magnetotransport anomalies in a new compound Gd2AgSi3

Abstract

Dc and ac–magnetic susceptibility (χ), specific heat (CP), electrical resistivity (ρ) and magnetoresistance measurements performed on the new polycrystalline compound Gd2AgSi3, crystallizing in the α–ThSi2 tetragonal structure, are reported. Two magnetic phase transitions were observed in dc and ac susceptibility, specific heat and resistivity measurements at temperatures TN1=11 K and TN2=20 K, despite a single site occupied by Gd atom, which is an indication of the complex magnetic behavior. Gd2AgSi3 turns out be one of the rare Gd compound in which a minimum is observed in the temperature dependence of resistivity in the paramagnetic state and also negative magnetoresistance over a wide temperature range (above TN2), mimicking the behavior of exotic Gd2PdSi3, in this ternary family. The isothermal magnetic entropy change, adiabatic temperature change, and refrigerant capacity reach a value of 9.5 J/kg-K, 7.5 K and 302 J/kg, respectively for the change of magnetic field 0-9 T.