Single crystal EPR studies on Mn(II)-doped sarcosine cadmium chloride and sarcosine cadmium bromide: study of zero-field splitting tensor in iso-structural complexes

EPR spectra of single crystals of Mn(II)-doped sarcosine cadmium chloride and sarcosine cadmium bromide are studied in Q-band and in X-band at room temperature. Two magnetically inequivalent sites are observed in both the lattices in a distorted octahedral environment. The spin-Hamiltonian parameters are extracted and are found to have a rhombic symmetry. The angular variation of the zero-field transitions is simulated for one of the sites with an asymmetric zero-field tensor D = 480 x 10(-4) cm(-1), E = -115 x 10(-4) cm(-1) and a = 10 x 10(-4) cm(-1) for Mn(II) in sarcosine cadmium chloride and with D = 460 x 10(-4) cm(-1) E = -98 x 10(-4) cm(-1) and a = 10 x 10(-4) cm(-1) for Mn(II) in sarcosine cadmium bromide. The observed large value of zero-field tensor is due to the steric effects of the crystal packing caused by the ligands. Matumura's plot predicts an average covalency of 8.8 and 7.7% for the manganese-ligand bond in SCC and SCB lattices respectively.