Neutron-diffraction and linear {Gr\"uneisen} parameter studies of magnetism in NdFe$_2$Ga$_8$

TL;DR

This study investigates the magnetic properties of NdFe$_2$Ga$_8$ using neutron diffraction and Grüneisen parameter measurements, revealing two magnetic transitions and complex magnetic structures with temperature-dependent behaviors.

Contribution

The paper provides new insights into the magnetic phase transitions and structures in NdFe$_2$Ga$_8$, combining neutron diffraction with thermodynamic measurements to clarify magnetic behavior.

Findings

Identification of two magnetic transitions at 10 K and 14.5 K.

Confirmation of an antiferromagnetic transition with a commensurate structure.

Observation of hysteresis in the Grüneisen parameter distinct from magnetization.

Abstract

We study the magnetism in NdFe$_2$Ga$_8$ by the neutron-diffraction and temperature-modulated linear {Gr\"uneisen} parameter measurements. Previous thermodynamical measurements have demonstrated that there are two magnetic transitions at 10 and 14.5 K, respectively. Neutron-diffraction measurements confirm that the lower one is an antiferromagnetic (AFM) transition with a commensurate magnetic structure. Both the commensurate and the incommensurate (IC) magnetic peaks are found below the higher transition but their intensities only gradually increase with decreasing temperature. Below 10 K, the commensurate peak intensity increases quickly with decreasing temperature, signaling the AFM transition, while the IC peak intensity disappears below 5 K. The linear {Gr\"uneisen} parameter along the $c$ axis, $\Gamma_c$, shows a hysteresis behavior that is different from the hysteresis behavior for the magnetization $M$. We give a discussion of the origin of the magnetism in NdFe$_2$Ga$_8$.