Metamagnetism, sign reversal and low temperature magnetocaloric effect in single-crystalline EuV₂Al₂₀

The Frank-Kasper cage compound EuV₂Al₂₀ crystallizes in the cubic structure with Fd3‾m space group and exhibits unusual magnetic and transport properties. The system undergoes an antiferromagnetic transition below 5.6 K wherein the Eu²⁺ moments are aligned anti-parallel along 〈1 1 1〉 direction and the system exhibits a weak metamagetic transition at the field of 1 T. Arrott plots (M² vs H/M) show a “S” shaped variation in the low fields below T_N and the plausible reason for the occurrence of negative slope is discussed. Isothermal magnetic entropy change is estimated from both magnetization and heat capacity measurements invoking the Maxwell's thermodynamic relations. Temperature variation of ΔS_m showed a weak negative minimum and a sign reversal at the field value of 1 T due to field induced metamagnetic transition. Universal master curve is constructed by rescaling the ΔS_m vs T curves in the context of analysing the nature of the magnetic transition.