Observation of dynamical diffraction phase due to neutron spin precession through a ferromagnetic crystal of permalloy

We have, for the first time, observed neutron spin precession due to a dynamical diffraction effect through a pair of ferromagnetic crystals of permalloy across a Bra,og condition of (200) by means of the neutron spin echo and phase echo principles. In spite of the imperfect crystal, the shift of Larmor precession is enhanced in the rocking curve of the transmitted beams at the magnetic Bragg condition. What was observed is a longer dwelling phase of up arrow spin neutron wave function due to the multiple reflection process of O-wave at Bragg reflection, against the rather freely passing opposite spin wave function. (C) 1999 Elsevier Science Ltd. All rights reserved.