EPR spectra and magnetization of XY-type rare-earth ions in pyrochlores Y2Ti2O7:Re3+ (RE=Yb, Er)

Abstract

The results of studies of Y2Ti2O7 single crystals doped with Er3+ and Yb3+ 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 Er3+ or Yb3+ ions were observed. Field dependences of magnetization of single crystals for magnetic fields directed along the crystallographic axes and temperature dependences of magnetic susceptibilities were measured. Spin Hamiltonian parameters (g-factors and parameters of the hyperfine interaction) for Er3+ and Yb3+ ions were obtained from analysis of experimental data. The registered EPR spectra and magnetization curves were successfully reproduced by simulations in framework of the crystal-field approach, in particular, with an account for hybridization of ground 4f13 configuration of Yb3+ ions with the charge transfer states.