Synthesis, structure, magnetic and magnetocaloric properties of hydrated terbium antimonate

Abstract

In recent years, the idea of using magnetic cooling based on the magnetocaloric effect as an alternative to vapor–gas cooling in liquefaction technology has attracted increasing attention from researchers due to its energy efficiency. The aim of the present research was the synthesis of hydrated terbium antimonate promising for magnetic cooling technology by hydrolysis and mechanochemical activation, and complex analysis of the influence of modifying elements on the physicochemical, magnetic and magneticaloric properties and structure of polyantimonic acid. As a result of studies, the methodology for the synthesis of hydrated terbium antimonate has been developed and it has been demonstrated that the phase formation in the fully substituted compound of Tb0.67Sb2O6∙(3 + n)H2O composition occurs after grinding and calcination at 200 °C as a result of ion-exchange reaction. The Curie-Weiss temperature was determined to be θCW = − 5 K. The magnetic ordering temperature has been extrapolated from TP(H) data, as µ0H = 0, to be about 0.98 K, where TP is the minimum of temperature dependences dM/dT curve and varies as a linear function of TP = 2.93·H + 0.98. The values of ΔS and of RC are about 3.8 Jkg−1K−1, 6.2 Jkg−1K− 1 and 18 Jkg−1, 89 Jkg−1 for µ0H = 2 T and 7 T, respectively at T = 3 K.