# Antiferromagnetism with divalent Eu in EuNi$_5$As$_3$

## TL;DR

This study synthesizes EuNi$_5$As$_3$ single crystals and characterizes their magnetic and electronic properties, revealing antiferromagnetic transitions associated with Eu$^{2+}$ moments and confirming the divalent, localized nature of Eu in the compound.

## Contribution

It provides the first comprehensive physical property analysis of EuNi$_5$As$_3$, demonstrating its antiferromagnetic behavior and Eu$^{2+}$ valence state through various experimental techniques.

## Key findings

- EuNi$_5$As$_3$ exhibits two antiferromagnetic transitions at 7.2 K and 6.4 K.
- The Eu ions are strongly divalent with localized Eu$^{2+}$ moments.
- Magnetic transitions are suppressed by an applied magnetic field.

## Abstract

We have successfully synthesized single crystals of EuNi$_5$As$_3$ using a flux method and we present a comprehensive study of the physical properties using magnetic susceptibility, specific heat, electrical resistivity, thermoelectric power and x-ray absorption spectroscopy (XAS) measurements. EuNi$_5$As$_3$ undergoes two close antiferromagnetic transitions at respective temperatures of $T_{N1}$ = 7.2 K and $T_{N2}$ = 6.4 K, which are associated with the Eu$^{2+}$ moments. Both transitions are suppressed upon applying a field and we map the temperature-field phase diagrams for fields applied parallel and perpendicular to the easy $a$ axis. XAS measurements reveal that the Eu is strongly divalent, with very little temperature dependence, indicating the localized Eu$^{2+}$ nature of EuNi$_5$As$_3$, with a lack of evidence for heavy fermion behavior.