Antiferro and ferromagnetic ordering in PrGe single crystal

TL;DR

This study reports on the growth, structure, and magnetic properties of PrGe single crystals, revealing two magnetic transitions and complex anisotropic behavior with implications for understanding magnetic ordering in rare-earth compounds.

Contribution

First detailed investigation of PrGe single crystal showing two magnetic orderings and anisotropic properties, with insights into its magnetic ground state and excitations.

Findings

PrGe exhibits two magnetic transitions at 44 K and 41.5 K.

The material shows large anisotropy in transport and magnetic properties.

Evidence of a gap in the spin-wave spectrum at low temperatures.

Abstract

The equiatomic PrGe single crystal was grown by Czochralski pulling method. The grown single crystal was found to have CrB-type orthorhombic crystal structure with the space group \textit{Cmcm} (#63). Transport and magnetization data reveal large anisotropy in the electrical resistivity, magnetic susceptibility and magnetization. PrGe was found to exhibit two consecutive magnetic orderings at 44 K and 41.5 K, respectively. The magnetic susceptibility measurement along the three principal directions, in low applied fields, revealed a cusp like behaviour at 44 K while at 41.5 K a ferromagnetic like increase was observed. The hysteritic behaviour in the magnetization measurement at 1.8 K confirmed the ferromagnetic nature of PrGe at low temperatures. The heat capacity data clearly revealed the bulk nature of two magnetic transitions by the presence of two sharp peaks attaining values exceeding 40 J/K$\cdot$mol at the respective temperatures. The absence of Schottky contribution in the magnetic part of heat capacity indicates a quasi-ninefold degenerate J=4 magnetic ground state in this system. The low temperature data of electrical resistivity and the magnetic part of heat capacity show an existence of gap in the spin-wave spectrum.