Temperature variation of the EPR spectra of Dy3+ in single crystal KY(WO4)(2)

EPR (electron paramagnetic resonance) studies of Dy3+ in single crystal KY( WO4)(2) have been carried out at X-band frequencies and in the temperature range of 6-43 K. The EPR spectrum is characterized by a strong anisotropy o f g factors [g(z)=14.60(2), g(x)=0.0(2), g(y)=1.54(3)]. It has been found t hat the fi-factor values decrease with increasing temperature (at T<30K Del ta g(z)/Delta T=-1.52x10(-2)K(-1): Delta g(y)/Delta T=-1.77X10(-3) K-1: at T>30 K Delta g(z)/Delta T=-6.2X10(-2) K-1: Delta g(y)/Delta T=- 3.03X10(-3) K-1). The superhyperfine structure from nuclei of tungstate W-183 (A(L)=95 X10(-4) cm(-1)) has been observed. A spin-lattice relaxation is shown to re sult from two Orbach processes through the first and second excited levels of an electronic spectrum.