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arXiv · 1812.11298

Magnetocaloric effect as a signature of quantum level-crossing for a spin-gapped system

Tanmoy Chakraborty·Chiranjib Mitra
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Abstract

Recent research dealing with magnetocaloric effect (MCE) study of antiferromagnetic (AFM) low dimensional spin systems have revealed a number of fascinating ground-state crossover characteristics upon application of external magnetic field. Herein, through MCE investigation we have explored field-induced quantum level-crossing characteristics of one such spin system: NH4CuPO4.H2O (NCP), an AFM spin 1/2 dimer. Experimental magnetization and specific heat data are presented and the data have been employed to evaluate entropy, magnetic energy and magnetocaloric properties. We witness a sign change in magnetic Grueneisen parameter across the level-crossing field B_C. An adiabatic cooling is observed at low temperature by tracing the isentropic curves in temperature-magnetic field plane. Energy-level crossover characteristics in NCP interpreted through MCE analysis are well consistent with the observations made from magnetization and specific heat data.

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Tanmoy Chakraborty, Chiranjib Mitra. 2018-12-29. Magnetocaloric effect as a signature of quantum level-crossing for a spin-gapped system. https://doi.org/10.1088/1361-648x/ab3962

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