Paramagnetic resonance evidence for anion fluctuations in the paraelectric phase of potassium dihydrogen phosphate

摘要

A marked nonlinear decrease of hyperfine splitting of the electron paramagnetic resonance spectrum of theI= 1/2 SeO3minus;4radical doped into potassium dihydrogen phosphate and an increase in the linewidth is observed with increasing temperature above 40thinsp;deg;C. The effects are shown to be a result of slow tumbling of the radical in the lattice. The slow tumbling is believed to be driven by orderndash;disorder fluctuations of the intrinsic phosphate anions which has been observed by NMR and neutron diffraction studies.