Significant inverse magnetocaloric effect induced by quantum criticality

The criticality-enhanced magnetocaloric effect (MCE) near a field-induced quantum critical point (QCP) in the spin systems constitutes very promising and highly tunable alternative to conventional adiabatic demagnetization refrigeration. Strong fluctuations low-$T$ regime can give rise large thermal entropy change thus significant cooling when approaching QCP. In this work, through efficient accurate many-body calculations, we show there exists inverse MCE (iMCE) spin-1 chain materials (${\mathrm{CH}}_{3}{)}_{4}\mathrm{NNi}{({\mathrm{NO}}_{2})}_{3}$ (TMNIN) ${\mathrm{NiCl}}_{2}\text{\ensuremath{-}}4\mathrm{SC}{({\mathrm{NH}}_{2})}_{2}$ (DTN), where DTN has substantial refrigeration capacity while requiring only moderate magnetic fields. iMCE characteristics, including temperature $\mathrm{\ensuremath{\Delta}}{T}_{\mathrm{ad}}$, isothermal $\mathrm{\ensuremath{\Delta}}S$, differential Gr\"uneisen parameter, rate, are obtained with calculations at finite temperature. performance, i.e., efficiency factor hold time, of two compounds is also discussed. Based on realistic models for spin-chain materials, conclude that compound coolant pronounced properties. We advocate such magnets be used cryofree space applications computing environments.