Near-Surface Structural Phase Transition of SrTiO$_3$ Studied with   Zero-Field $\beta$-Detected Nuclear Spin Relaxation and Resonance
  We demonstrate that zero-field $\beta$-detected nuclear quadrupole resonance and spin relaxation of low energy $^8$Li can be used as a sensitive local probe of structural phase transitions near a surface. We find that the transition near the surface of a SrTiO$_3$ single crystal occurs at $T_c \sim 150$ K, i.e., 45 K higher than $T^{bulk}_c$, and that the tetragonal domains formed below $T_c$ are randomly oriented. 
Z. Salman, R.F. Kiefl, K.H. Chow, M.D. Hossain, T.A. Keeler, S.R.   Kreitzman, C.D.P. Levy, R.I. Miller, T.J. Parolin, M.R. ...