Large magneto-thermal effect and the spin-phonon coupling in a parent   insulating cuprate Pr_{1.3}La_{0.7}CuO_4
  The magnetic-field (H) dependence of the thermal conductivity \kappa of Pr_{1.3}La_{0.7}CuO_4 is found to show a pronounced minimum for in-plane fields at low temperature, which is best attributed to the scattering of phonons by free spins that are seen by a Schottky-type specific heat and a Curie-Weiss susceptibility. Besides pointing to a strong spin-phonon coupling in cuprates, the present result demonstrates that the H-dependence of the phonon heat transport should not be naively neglected when discussing the \kappa(H) behavior of cuprates, since the Schottky anomaly is ubiquitously found in cuprates at any doping. 
X. F. Sun, I. Tsukada, T. Suzuki, Seiki Komiya, Yoichi Ando