Spin-lattice relaxation in the mixed state of the high-$T_c$ cuprates: electronic spin-flip scattering versus spin-fluctuations

摘要

Recent experimental and theoretical studies have established that thespin-lattice relaxation rate, $1/T_1$, measured in nuclear magnetic resonance(NMR) experiments is a site-sensitive probe for the electronic spectrum in themixed state of the high-$T_c$ cuprates. While some groups suggested that$1/T_1$ is solely determined by spin-flip scattering of BCS-like electrons,other groups stressed the importance of antiferromagnetic spin-fluctuations. Weshow that these two relaxation mechanisms give rise to a {\it qualitatively}different temperature and frequency dependence of $^{17}$O $1/T_1$. Acomparison of our results with the experimental $^{17}$O $1/T_1$ data providessupport for a relaxation mechanism dominated by antiferromagneticspin-fluctuations.