Spin and charge excitations in YBa2Cu3O7: Constraints from spin-relaxation rates in the normal state

Abstract

We analyze the measured Cu spin-relaxation data for a single crystal of ${\mathrm{YBa}}_2$ ${\mathrm{Cu}}_3$ ${\mathrm{O}}_7$ and deduce, within 30%, the relevant hyperfine couplings, and the associated fluctuation times, for Cu nuclei in the planar and chain sites. We discuss constraints placed thereby on one- and two-component theories. Our deduced values for the hyperfine couplings are in good agreement with the quantum-chemical analysis proposed by Mila and Rice.