Structural, magnetic, thermodynamic and electrical transport properties of a new compound $\mbox{Pr}_2\mbox{Rh}_{2}\mbox{Ga}$

TL;DR

This study reports the synthesis and comprehensive characterization of a new intermetallic compound Pr2Rh2Ga, revealing its ferromagnetic transition at 18 K, metallic behavior, significant magnetocaloric effects, and second-order phase transition.

Contribution

The paper introduces a new Pr-based intermetallic compound with detailed structural, magnetic, thermodynamic, and transport properties, including magnetocaloric effects and phase transition analysis.

Findings

Pr2Rh2Ga crystallizes in orthorhombic structure with space group Cmca.

Exhibits ferromagnetic transition at 18 K.

Displays significant magnetocaloric effects near transition temperature.

Abstract

A new ternary intermetallic compound $\mathrm{Pr_2Rh_2Ga}$ was synthesized by arc-melting and was characterized by powder X-ray diffraction (PXRD), magnetization, heat capacity $\mathrm{C}_p(\textit{T})$, and electrical resistivity $\rho(T)$ measurements. PXRD patterns revealed that $\mathrm{Pr_2Rh_2Ga}$ crystallizes in the $\rm{La_2Ni_3}$-type of orthorhombic structure with the space group $Cmca$. The temperature variation of magnetic susceptibility, $\mathrm {C}_p(\textit{T})$ and $\rho(T)$ confirmed that $\mathrm{Pr_2Rh_2Ga}$ exhibits a ferromagnetic behavior with the transition temperature of 18 K. The estimated Sommerfeld coefficient $\gamma$ = 640 mJ/($\mathrm{Pr.mole.K^2}$) from the $\mathrm {C}_p(\textit{T})$ results in the paramagnetic region just above $T_{C}$~was large in comparison to ordinary metals. In the paramagnetic region $\rho(T)$ data showed a metallic behavior characteristic of electron - phonon scattering. The maximum negative magneto-resistance at high field occurs in the region near the magnetic phase transition temperature. The maximum value of magnetic entropy change ($\rm -\Delta \textit{S}_{M}$) and adiabatic temperature change ($\rm \Delta \textit{T}_{ad}$) are $\rm8.2~J/kg.K$ and $\rm3.6~K$, respectively, around the transition temperature for the change of magnetic field 0-9 T. The calculated refrigerant capacity is $\rm70~J/kg$, and $\rm135~J/kg$ for a change of magnetic field 0-5 T and 0-9 T, respectively. Arrott plot derived from isothermal magnetization and the universal scaling plot by normalizing $\rm -\Delta \textit{S}_{M}$ confirm that the compound undergoes a second order ferromagnetic to paramagnetic phase transition.