High-resolution alternating-field technique to determine the magnetocaloric effect of metals down to very low temperatures

TL;DR

This paper introduces a low-frequency alternating field method for precise, continuous measurement of the magnetocaloric effect in small metal samples at very low temperatures, enhancing accuracy and efficiency especially near quantum critical points.

Contribution

The paper presents a novel low-frequency alternating field technique enabling high-precision, continuous measurements of the magnetocaloric effect on small samples at very low temperatures.

Findings

The technique allows faster and more accurate determination of $ ext{Gamma}_H(T)$.

Application to doped YbRh$_2$Si$_2$ demonstrates improved measurement precision.

The method is effective for studying quantum criticality in metals.

Abstract

The magnetocaloric effect or "magnetic Gr\"uneisen ratio" $\Gamma_H=T^{-1}(dT/dH)_S$ quantifies the cooling or heating of a material when an applied magnetic field is changed under adiabatic conditions. Recently this property has attracted considerable interest in the field of quantum criticality. Here we report the development of a low-frequency alternating field technique which allows to perform continuous temperature scans of $\Gamma_H(T)$ on small single crystals with very high precision and down to very low temperatures. Measurements on doped YbRh$_2$Si$_2$ show that $\Gamma_H(T)$ can be determined with this technique in a faster and much more accurate way than by calculation from magnetization and specific heat measurements.