EPR study of Er3+ crystal-field and Ho-165(3+)-Er3+ interactions in singlecrystals of HoxY1-xVO4 (x=0.02-1.00) - art. no. 094435

Liquid-helium temperature electron paramagnetic resonance (EPR) spectra of the Er3+ ion in single crystals of HoxY1-xVO4 (x=0.02- 1.0) are exploited t o reveal the influence of the crystal-field and Er3+-Ho3+ interactions. The Er3+ g value at 4 K in the lightly doped samples (x<0.3) was here successf ully accounted for by the estimated crystal-field parameters (cm(-1)): B-2( 0) = -108.0, B-4(0) = 40.0, B-6(0) = 40.0, B-4(4) = 949.0, B-6(4) = 26.0, w hile that in the concentrated paramagnetic samples (x = 0.9, 1.0) by the pa rameters (cm(-1)): B-2(0) = -114.8, B-4(0) = 46.9, B-6(0) = =43.8, B-4(4) = -971.4, B-6(4) = 91.9.The shift of the Er3+ value in the paramagnetic HoxY 1-xVO4 crystals (x = 0.9, 1.0) from that in the diamagnetic YVO4 crystal ha s been analyzed to estimate the value of the parameter gamma (= -2.2 cm(-1) ) describing the diagonal element of the symmetric tensor representing Ho3-Er3+ interactions. The unresolved EPR linewidth of the Er3+ ion is account ed for by the indirect superhyperfine interaction (A(parallel to)) of the E r3+ ion with the surrounding Ho-165 nuclei, estimating A(parallel to) = 0.0 026 cm(-1). In addition, the absolute value of the parameter epsilon, an of f-diagonal element of the antisymmetric tensor describing Ho3+-Er3+ interac tions. has been estimated to be \ epsilon \ = 0.029 cm(-1).