title: Nonlinear effects from dipolar interactions in hyperpolarized liquid 129Xe.
abstract: We investigate nonlinear effects of long-range dipolar interactions in a spherical sample of hyperpolarized liquid 129Xe. Using two high-T(c) SQUID detectors we directly measure the evolution of the magnetization gradients. For small initial rf tip angles we observe an increase in the transverse relaxation time T2* by a factor of 5 and coherent oscillations of magnetization gradients. For large tip angles we observe an exponential growth of the magnetization gradients and demonstrate a gain in sensitivity to magnetic field gradients by a factor of 10. Our results are in quantitative agreement with simple analytical predictions. We discuss applications of these nonlinear effects for precision measurements.
authors.affiliation: Department of Physics, Princeton University, Princeton, New Jersey 08544, USA.
authors.forename: M P
authors.initials: MP
authors.lastname: Ledbetter
authors.forename: M V
authors.initials: MV
authors.lastname: Romalis