Magnetic Properties of KGd(WO4)2 Single Crystal Studied by EPR Spectroscopy

Magnetic properties of magnetically concentrated KGd(WO4)2 single crystal are studied using EPR spectroscopy. The EPR spectra are broad and have a complex shape, showing contributions of a few gadolinium centers. Temperature dependence of the total intensity of the EPR spectra and the inverse of the total intensity reveal two temperatures when the behavior of the total intensity suddenly changes, first one at 66.8 ± 3.3 K and the second one at 9.9 ± 2.8 K. Detailed analysis of this dependence suggests the presence of different magnetic systems of the Gd 3+ ions. The EPR spectra were described by the spin Hamiltonian of monoclinic symmetry with electron spin S = 7/2, for which all g-matrix components and fine-structure parameters have been determined using EPR-NMR program. Raman spectra measured at low temperatures do not differ significantly from the one measured at room temperature. The analysis has given a deeper insight into different kinds of magnetic interactions between paramagnetic Gd 3+ centers in KGd(WO4)2 single crystal.