Field-rotational magnetocaloric effect: A new experimental technique for accurate measurement of the anisotropic magnetic entropy

TL;DR

This paper introduces a novel experimental technique leveraging the rotational magnetocaloric effect to accurately and efficiently measure the anisotropic magnetic entropy in materials, demonstrated on a spin-ice compound.

Contribution

A new high-resolution, rapid measurement method for entropy as a function of magnetic field angle using the rotational magnetocaloric effect.

Findings

Good agreement between measured and theoretical entropy in Dy2Ti2O7

Technique enables precise angle-resolved entropy measurements

Provides a new approach for studying complex condensed-matter systems

Abstract

We developed a new technique for measuring the thermodynamic entropy as a function of the magnetic field angle. This technique enables high-resolution angle-resolved measurements of the entropy in an unprecedentedly short measuring time. When the magnetic field is rotated under adiabatic conditions, the sample temperature changes owing to the field-angle variation of its entropy, which is referred to as the rotational magnetocaloric effect. By investigating this effect along with the specific heat, the field-angle dependence of the entropy can be determined. To demonstrate this technique, we chose the spin-ice compound Dy$_2$Ti$_2$O$_7$ as a benchmark and showed good agreement between the measured and theoretical entropies as a function of the field angle. This development provides a new approach to studying condensed-matter physics, in which multiple degrees of freedom play an important role.