Fluctuations and correlations in SrTiO3 for T>~Tc

The linewidth broadening of the paramagnetic resonance of the Fe3+-VO center in SrTiO3 near Tc has been measured accurately and analyzed for T→Tc+. It is found that the order-parameter susceptibility χ(q→,T) is two-dimensionally anisotropic with an anisotropy parameter Δ=160. The critical exponent of the correlation length ξ is found to be ν=0.63±0.07. The EPR linewidth is cusp shaped for T→Tc+ and finite at T=Tc. © 1972 The American Physical Society.