Thermal expansion, heat capacity and magnetostriction of RAl$_3$ (R = Tm, Yb, Lu) single crystals

TL;DR

This study investigates the thermal expansion, heat capacity, and magnetostriction of RAl3 (R = Tm, Yb, Lu) single crystals, revealing valence states, crystal electric field effects, and quantum oscillations.

Contribution

It provides new experimental data on RAl3 compounds, including de Haas-van Alphen oscillations and CEF splitting, enhancing understanding of their electronic and magnetic properties.

Findings

YbAl3 shows intermediate valence behavior.

de Haas-van Alphen oscillations observed in YbAl3 and LuAl3.

CEF splitting scheme determined for TmAl3.

Abstract

We present thermal expansion and longitudinal magnetostriction data for cubic RAl3 (R = Tm, Yb, Lu) single crystals. The thermal expansion coefficient for YbAl3 is consistent with an intermediate valence of the Yb ion, whereas the data for TmAl3 show crystal electric field contributions and have strong magnetic field dependencies. de Haas-van Alphen-like oscillations were observed in the magnetostriction data of YbAl3 and LuAl3, several new extreme orbits were measured and their effective masses were estimated. Zero and 140 kOe specific heat data taken on both LuAl3 and TmAl3 for T < 200 K allow for the determination of a CEF splitting scheme for TmAl3.