Magnetoresistance variation and noise properties of chevron stretcher detectors

Abstract

The angular variation of the magnetoresistance of one‐ and two‐level chevron stretcher detectors has been determined and related to the underlying microscopic domain configuration. The origin of the 1ω‐2ω transition (where ω is the angular frequency of the rotating field) in one‐level detectors is shown to be the result of incomplete magnetization reversal along the detector. The characteristics of this transition and the associated output are discussed for 28‐ and 20‐μm‐period devices. Also discussed are the amplitude‐ and phase‐shift modes of operation of these detectors for normal drive fields. Noise measurements made on zero‐ and one‐state detector outputs show that both states exhibit a √N noise dependence with the number of chevrons N and that the drive‐field dependence of the noise is approximately 1/H_xy at large drive fields. Comparison of the noise output from different detector geometries is made.