DYNAMIC POLARIZATION OF NUCLEI BY ELECTRON NUCLEAR DIPOLAR COUPLING IN CRYSTALS
Abstract
An investigation was made of the dynamic polarization of the protons in (Ce, La)2 Mg3(NO3)12. 24H2O which occurs when one saturates the forbidden microwave transitions that simultaneously flip a proton spin and a Ce(3+) electron spin. The rate equations for the electron and nuclear polarization are solved for (a) a simple ideal model; b) a model for the case where the forbidden lines are not resolved; and (c) a model taking into account nuclear spin temperature diffusion. An apparatus for simultaneous observation of proton magnetic resonance and Ce(3+) paramagnetic resonance at liquid helium temperatures is described. The proton polarization is observed for a number of different concentrations of Ce(3+). The magnitude of the polarization, its dependence on magnetic field and microwave power, and the transient behavior are qualitatively explained. In a crystal containing 1% Ce, the proton polarization is observed to become greater than the thermal equilibrium value by the factor 150, which is about one-quarter of the theoretical ideal. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1961
- Accession Number
- AD0251224
Entities
People
- C.d. Jeffries
- O.s. Leifson
Organizations
- University of California, Berkeley