EPR spectra and magnetization of XY-type rare-earth ions in pyrochlores Y2Ti2O7: RE3+ (RE=Yb, Er)

Abstract

The results of studies of Y 2 Ti 2 O 7 single crystals doped with Er 3+ or Yb 3+ ions by means of electron paramagnetic resonance (EPR) and dc-magnetometry are reported. EPR signals of the trigonal centers with the characteristic hyperfine structure of Er 3+ or Yb 3+ ions were observed. Field dependences of the magnetization of single crystals for magnetic fields directed along the crystallographic axes and temperature dependences of the magnetic susceptibilities were measured. Spin Hamiltonian parameters (g-factors and parameters of the hyperfine interaction) for the Er 3+ and Yb 3+ ions were obtained from the analysis of the experimental data. The registered EPR spectra and magnetization curves are successfully reproduced by simulations in the framework of the crystal-field approach, in particular, with an account for a hybridization of the ground 4f 13 configuration of Yb 3+ ions with the charge transfer states. PACS: 71.70.Ch, 75.10.Dg, 76.30.Kg.