Magnetocaloric properties of LaFe$_{13-x-y}$Co$_x$Si$_y$ and commercial grade Gd

TL;DR

This study compares the magnetocaloric properties of LaFeCoSi alloys with commercial Gd, revealing their potential for magnetic refrigeration with detailed measurements of entropy change, heat capacity, and temperature change.

Contribution

It provides the first detailed comparison of LaFeCoSi alloys' magnetocaloric effects with Gd, including corrected measurements for demagnetization effects.

Findings

LaFeCoSi alloys exhibit higher entropy change than Gd at 1 T.

Measured adiabatic temperature changes are around 2.1-2.3 K for LaFeCoSi.

Gd shows a higher adiabatic temperature change of 3.3 K.

Abstract

The magnetocaloric properties of three samples of LaFe$_{13-x-y}$Co$_x$Si$_y$ have been measured and compared to measurements of commercial grade Gd. The samples have (x=0.86, y=1.08), (x=0.94, y=1.01) and (x=0.97, y=1.07) yielding Curie temperatures in the range 276-288 K. The magnetization, specific heat capacity and adiabatic temperature change have been measured over a broad temperature interval. Importantly, all measurements were corrected for demagnetization, allowing the data to be directly compared. In an internal field of 1 T the maximum specific entropy changes were 6.2, 5.1 and 5.0 J/kg K, the specific heat capacities were 910, 840 and 835 J/kg K and the adiabatic temperature changes were 2.3, 2.1 and 2.1 K for the three LaFeCoSi samples respectively. For Gd in an internal field of 1 T the maximum specific entropy change was 3.1 J/kg K, the specific heat capacity was 340 J/kg K and the adiabatic temperature change was 3.3 K. The adiabatic temperature change was also calculated from the measured values of the specific heat capacity and specific magnetization and compared to the directly measured values. In general an excellent agreement was seen.