Crystal structure and low-energy Einstein mode in ErV$_2$Al$_{20}$ intermetallic cage compound

TL;DR

This study reports the synthesis, crystal structure, and physical properties of ErV$_2$Al$_{20}$, revealing a low-energy Einstein mode and paramagnetic behavior at low temperatures, contributing to understanding intermetallic cage compounds.

Contribution

It provides the first detailed characterization of ErV$_2$Al$_{20}$, including its structure and low-energy vibrational mode, expanding knowledge of intermetallic cage compounds.

Findings

ErV$_2$Al$_{20}$ is a Curie-Weiss paramagnet down to 1.95 K.

Identified a low-energy Einstein mode with $ heta_E$ = 44 K.

The compound exhibits a broad heat capacity anomaly at low temperatures.

Abstract

Single crystals of a new ternary aluminide ErV$_2$Al$_{20}$ were grown using a self-flux method. The crystal structure was determined by powder X-ray diffraction measurements and Rietveld refinement, and physical properties were studied by means of electrical resistivity, magnetic susceptibility and specific heat measurements. These measurements reveal that ErV$_2$Al$_{20}$ is a Curie-Weiss paramagnet down to 1.95 K with an effective magnetic moment $\mu_{eff}$ = 9.27(1) $\mu_B$ and Curie-Weiss temperature $\Theta_{CW}$ = -0.55(4) K. The heat capacity measurements show a broad anomaly at low temperatures that is attributed to the presence of a low-energy Einstein mode with characteristic temperature $\Theta_E$ = 44 K, approximately twice as high as in the isostructural 'Einstein solid' VAl$_{10.1}$.