Spin-Phonon Contributions to the b⁰₂Parameter for Gd³⁺in RbCdF₃Single Crystals

Abstract

Temperature dependence of the b02s p i n -h a m i l t o n i a n p a r a m e t e r f o r G d3 + in RbCdF3 single crystals is described. The dependence is interpreted in terms of the 4f 7 electrons coupling to the whole phonon spectrum of the crystal. The presented data give also an insight into the dynamics of charge compensators causing a tetragonal distortion of the crystal field.

Gd3+Spin-Phonon Interactions in Rare-Earth Fluoride Crystals

“…The coupl i ng of the 4 7 electro ns to the who le pho non spectrum stro nger tha n i n our crysta l s exists i n the G d 3 + -do p ed R bCdF 3 singl e crysta l , due to the dyna m ics of charg e comp ensato rs causing a tetra gona l di storti on of the crysta l Ùel d. The val ue of 2 = À 0 7 7 3 5 (2 4 ) G Hz for G d 3 + -dop ed R bCdF 3 was determ ined fro m the tem pera ture dep endence of b 0 2 [22], as com pa red to K 2 = 0 : 2 2 1 9 (1 7 ) G Hz for La F 3 or K 2 = 0 : 1 4 8 0 (1 ) GHz for Li YF 4 . On the other ha nd, i n G d 3 + -do p ed PbF 2 sing l e crysta l the val ue of K 2 = À 0 : 1 0 7 9 G Hz for tetra gona l deform ati ons and K 2 = 0 : 3 6 8 8 G Hz for tri gona l deform ati ons wa s obta i ned f rom EPR uni axi al stress exp eri ment i n the tem pera ture ra nge 130{ 600 K by Kuri ata et al .…”

“…There i s no tem p erature dep endence for the sixth ra nk SHP i n the ab o ve singl e crysta l s. Thus, fro m the tem p erature dep endence o f ñ 2 we can see spi n{ pho no n intera cti ons, since thi s para m eter i s very sensiti ve to the tem pera ture-induced di storti on of the crysta l Ùel d. In order to descri b e the tem pera ture dep endence of ñ 2 pl otted i n Fi g. 1 we used the D ebye m odel , whi ch assumes tha t pa ra magneti c i ons G d 3 + are coupl ed to the who l e pho no n spectrum of the crysta l l atti ce. The equati on ado pted to Ùt ñ 2 to tem p erature i s the fol l owi ng [22]:…”

Parametrization of the Vibronic Contributions to the b04Spin-Hamiltonian Parameters for8S7/2Ground State Ions in Fluoroperovskites

“…[1][2][3][4][5][6]) with the contributions due to the thermal expansion of a crystal lattice being insignificant,…”