ELECTRON-PARAMAGNETIC-RESONANCE STUDY OF MN2-ION-DOPED NICKEL BIS (HYDROGEN MALEATE) HEXAHYDRATE SINGLE-CRYSTALS()

Mn2+-doped nickel bis (hydrogen maleate) hexahydrate single crystals h ave been studied by electron paramagnetic resonance (EPR) from room te mperature to liquid nitrogen temperature at X-band. From the observed EPR spectrum the spin-Hamiltonian parameters have been evaluated and t he Mn2+ was found to substitute for Ni2+ ions in the host lattice. The observation of unusual well resolved Mn2+ spectrum at room temperatur e and its broadening on lowering the temperature in Ni[C4H3O4](2) . 6H (2)O:Mn2+ single crystals have been explained in terms of the 'spin-qu enching concept'. The observed shift in the g-factor of the Mn2+ ion f rom that in diamagnetic hosts is probably due to the Ni2+ ions, which produce a local static magnetic field at the site of Mn2+ ions. The co valency percentage of the Mn-O bond has been estimated to be 9.2%. (C) 1998 Elsevier Science B.V. All rights reserved.