Nuclear spin relaxation in ionic dielectrics at low temperatures via conduction electrons in metallic covering

Abstract

We propose a method of obtaining of polarized nuclei in a crystal of ionic insulator, which is placed in a magnetic field and cooled to cryogenic temperatures. Polarization is a result of inelastic scattering of the conduction electrons of the metallic covering of a sample from the nuclei. This method (in a simplified form without the magnetic field) is suitable for obtaining aligned nuclei. We have derived the formulas (a) for the cross section of the process of electron-nucleus inelastic scattering, and (b) for the longitudinal relaxation time ${T}_{1}$. As an example, we consider the spin relaxation process for the ${}^{93}$Nb nucleus inside the Nb${}_{2}$O${}_{5}$ dielectric sample with a gold covering.