Critical dynamics in SrTio3 from paramagnetic resonance

Abstract

Paramagnetic resonance line shapes and linewidths of the Fe3+-V0 center in SrTiO3 above Tc permit the determination of an effective relaxation rate l(T) for the local rotations of the oxygen octahedra by observation of the crossover from Lorentzian to Gaussian line shapes with different settings of the applied field. We find that l decreases as TTc+, clearly indicating critical slowing down. In addition, the relaxation rate c for the R-point (order-parameter) collective mode is estimated from the line-widths in the region of Lorentzian shapes, indicating a "central peak" of width c0.6×108 invsec0.1l at T=Tc+2 K. © 1974 The American Physical Society.