Nuclear spin-lattice relaxation and Knight shift in YBa2Cu4O8

The temperature dependences of the 63Cu nuclear spin-lattice relaxation rate 1/T1 and Knight shift K in YBa2Cu4O8 have been measured by nuclear quadrupole resonance (NQR) and nuclear magnetic resonance (NMR) techniques. In the normal state, both the 1T1 for the Cu(2) sites and the in-plane component of the Knight shift K2⊥ increase rapidly with temperature from Tc up to about 250 K. Approximate T-linear temperature dependence of 1T1 was observed in a wide temperature range between 250 and 680 K, that is in general accord with previous analyses.