# Magnetic, Transport, and Phonon Properties of the Trivalent Eu Metallic Compound EuBe13

## TL;DR

This study investigates EuBe13's magnetic, thermal, and electrical properties, revealing Eu3+ valence state, coexistence of phonon modes, and unusual resistivity behavior, contributing to understanding of Eu-based intermetallic compounds.

## Contribution

First comprehensive analysis of EuBe13's phonon, magnetic, and transport properties, clarifying Eu valence state and phonon mode coexistence in this compound.

## Key findings

- EuBe13 exhibits Eu3+ valence state despite large Eu–atom distances.
- Coexistence of Debye and Einstein phonon modes with specific temperatures.
- Unusual T-cubed resistivity dependence at low temperatures.

## Abstract

Magnetic susceptibility, specific heat, and electrical resistivity measurements have been performed on single-crystal EuBe13 in the temperature range between 2 and 300 K to investigate its phonon property and the valence state of the Eu ion. The obtained temperature dependence of the magnetic susceptibility curves obey a typical Van Vleck susceptibility for Eu3+ with a nonmagnetic ground state in the entire measured temperature range. In the case of the specific heat, we observed the coexistence of Debye and Einstein phonon modes with characteristic Debye and Einstein temperatures of ~ 835 K and ~167 K, respectively, which are in good agreement with those previously reported for other isostructural MBe13 compounds (M = rare earths and actinides). The temperature dependence of the resistivity for EuBe13 shows an unusual T-cubed like dependence at low temperatures, as also observed for the nonmagnetic isostructural compound LaBe13, which can be reproduced well by calculations based on electron--phonon scattering using the estimated Debye temperature and Einstein temperature. We also summarized the relationship between the Eu-valence state and the free distance between the Eu ion and the first-nearest-neighbor atoms in several Eu-based cubic compounds, and argued that EuBe13 takes the Eu3+ state despite its larger free distance than other Eu3+ compounds.