Surface Relaxation Times of Conduction-Electron Spins in Superconductors and Normal Metals

Electron spin relaxation times in surface collisions were deduced from measurements on superconductors of the NMR Knight shift, critical magnetic fields, and tunneling conductance as well as from measurements on normal metals by conduction-electron spin resonance. The relaxation times ${\tau }_{\mathrm{so}}$ as determined by the various methods are consistent and depend on the atomic number of the metal in a manner similar to that proposed by Abrikosov and Gor'kov.