Nonlinear dynamics of a magnetization subject to RF feedback field:new experimental evidence

摘要

In a recent study,the dynamics of large magnetization subject to a RF feedback field from the detection circuit of the probe was investigated both theoretically and experimentally.A simple model including non-linear modification of the Bloch equations allowed us to predict the occurrence of repeated bursts of NMR transverse magnetization during evolution(named self-sustained maser pulses).However,the decay of the amplitude of these repeated maser pulses with a characteristic time 4T_1 predicted by this simple model could not be observed and the experiments showed a regime of non-attenuated self-sustained maser pulses.This was interpreted as a direct consequence of B_0 inhomogeneities.In this paper we present new experimental evidence that support this assumption and that further demonstrate the role of B_0 inhomogeneity.To cite this article :A.Louis-Joseph et al.,C.R.Chimie 7(2004).