Critical behavior of quasi-2D organic-inorganic halide perovskite (C6H5CH2CH2NH3)<s ub>2CuCl4 single crystals

초록

Critical behavior of quasi two-dimensional organic-inorganic halide perovskites (C6H5CH2CH2NH3)(2)CuCl4 is investigated using magneto-thermal and isothermal magnetic properties along the easy axis. Banerjee's criterion indicates that phase transition from paramagnetic to ferromagnetic phases below TC = 9.4 K is of second-order. Scaling analysis reveals that critical exponent beta from spontaneous magnetization in the critical region below TC and delta from critical isotherm at TC are found to be 0.22(3) and 9.28-9.4, close to 2D finite XY model. Meanwhile, gamma from magnetic susceptibility in the critical region above TC is gradually decreased from 2.4 at high-temperature region. Critical exponents from magneto-thermal properties are found to be consistent with those determined from magnetization isotherms. The reliability of critical values is verified using the scaling hypothesis. Our results evidence that (C6H5CH2CH2NH3)(2)CuCl4 crossovers from isotropic 2D Heisenberg to anisotropic 3D models towards TC and can be promising candidates for magnetocaloric materials for hydrogen reliquefaction.

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