Double magnetic phase transitions and magnetotransport anomalies in a new compound Gd$_\textbf{2}$AgSi$_\textbf{3}$

TL;DR

This study reports the discovery of a new Gd-based compound, Gd2AgSi3, exhibiting two magnetic phase transitions, complex magnetic behavior, and notable magnetotransport anomalies such as resistivity minima and negative magnetoresistance.

Contribution

It provides the first detailed characterization of Gd2AgSi3, revealing its unique magnetic transitions and magnetotransport properties in a previously unstudied compound.

Findings

Two magnetic phase transitions at 11 K and 20 K.

Observation of resistivity minimum in the paramagnetic state.

Negative magnetoresistance over a wide temperature range.

Abstract

Dc and ac-magnetic susceptibility ($\chi$), specific heat ($C_\mathrm{P}$), electrical resistivity ($\rho$) and magnetoresistance measurements performed on the new polycrystalline compound $\mathrm{Gd_2AgSi_3}$, crystallizing in the $\alpha$-$\mathrm{ThSi_2}$ tetragonal structure, are reported. Two magnetic phase transitions were observed in dc and ac susceptibility, specific heat, and resistivity measurements at temperatures $\mathrm{T_{N_1}} = 11$ K and $\rm{T_{N_2}} = 20$ K, despite a single site occupied by Gd atom, which is an indication of the complex magnetic behavior. $\mathrm{Gd_2AgSi_3}$ turns out to 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 $\rm{T_{N_2}}$), mimicking the behavior of exotic $\mathrm{Gd_2PdSi_3}$, in this ternary family. The isothermal magnetic entropy and adiabatic temperature changes reach a value of 9.5 J/kg-K and 7.5 K respectively for the field change of 9 T.