3D long-range magnetic ordering in (C2H5NH3)2CuCl4 compound revealed by internal magnetic field from muon spin rotation and first principal calculation

We report the results of muon spin rotation measurement that reveal a 3D long-range magnetic ordering in the inorganic CuCl4 layers separated by (C2H5NH3) organic ligands. The measured temperature dependent internal magnetic field down to 300 mK shows the 3D long-range magnetic ordering with magnetic transition at the Neel temperature of TN = 10.06 K and critical exponent of 0.31. The ground state internal dipole field is calculated by considering muon zero-point motion effect at the muon stop position determined by first principal DFT calculation, in combination with magnetization density calculated on the basis of a specific magnetic structure model. The calculated result is shown in good agreement with the measured value of internal field at the ground state temperature, thereby justifying the magnetic structure model adopted for this system and explaining the 3D nature of magnetic ordering. This model may therefore be applicable to the study of other magnetic materials.