Study of the crystal field and rare-earth magnetism in YF3:Yb3+

Abstract

The electron paramagnetic resonance spectra (X-band, f ~ 9.42 GHz) of Yb3+ ions have been measured at temperature 15 K in YF3:Yb3+ single crystals. The principal values of the g-tensors, gb = g1 = 1.67, g2 = 2.42, g3 = 5.41, and directions n1 = [0, 1, 0], n2 = [±sin(54.8°), 0, cos(54.8°)], n3 = [∓sin(35.2°), 0, cos(35.2°)] of the corresponding principal axes for the Yb3+ ions which replace Y3+ ions at two magnetically nonequivalent sites with the local Cs symmetry in the orthorhombic crystal lattice have been obtained from analysis of the angular dependences of the spectra taken in the static magnetic fields lying in the crystallographic (bc) and (ac) planes. Experimental data are interpreted in the frameworks of the crystal field theory. Using the obtained set of crystal field parameters for Yb3+ ions in the YF3 host related to the crystallographic system of coordinates, we can reproduce satisfactorily the crystal field energies of Yb3+ ions determined earlier from optical measurements