EPR Detection of Hyperfine Couplings from203Tl++and205Tl++Ions and Ferroelectric-Symmetry Signals in Paraelectric KH2PO4and KD2PO4

Abstract

By using computer simulation techniques, it is possible to understand the rather unusual superhyperfine pattern on the hyperfine transitions of TIZ+ ( 6 s ' ) ions and to resolve transitions from '03T12+ and 205T11+ for the first time in the KH2P04-type lattices. The detection of ferroelectric excitations in the paraelectric phase of partially deuterated KH,PO. and their dependence on the H/D ratio could not be explained in terms of current theoretical models of ferroelectric transitions.