A Measuring System for Analyzing AC Dynamic Domain Wall Motions in Bubble Materials

A measuring system is described which is capable of rapidly analyzing dynamic ac domain wall displacements monitored by Faraday photometric signals from bubble materials placed in a polarizing microscope. An audio modulated rf drive field used in conjunction with signal processing electronics produces a signal proportional to the derivative dx/dhpof the displacement amplitude with respect to the peak drive field. This signal is the basis of plots produced automatically of dx/dhpversus frequency (10 kHz - 32 MHz), dxldhpversus hp, and x versus hp. Data obtained on an epitaxial garnet film of EU0.7 Y2.3Fe3.85Ga1.15O12 are presented showing domain wall resonances and nonlinearities between wall velocity and drive field. © 1973, IEEE. All rights reserved.