Electron Spin-Lattice Relaxation of doped Yb3+ ions in YBa2Cu3Ox
  The electron spin-lattice relaxation (SLR) times T1 of Yb3+&#135; ions were measured from the temperature dependence of electron spin resonance linewidth in Y0.99Yb0.01Ba2Cu3Ox with different oxygen contents. Raman relaxation processes dominate the electron SLR. Derived from the temperature dependence of the SLR rate, the Debye temperature (Td) increases with the critical temperature Tc and oxygen content x. Keywords: EPR; ESR; Electron spin-lattice relaxation; Debye temperature; Critical temperature 
L.K. Aminov, V.A. Ivanshin, I.N. Kurkin, M.R. Gafurov, I.Kh. Salikhov,   H. Keller, M. Gutmann