Magnetoresistive sensors with rapidly solidified Permalloy fibers

The microstructure and properties of Permalloy fibers were studied. Both transverse and longitudinal extraordinary magnetoresistive effects have a positive initial slope due to stress-related rotation of moments in the closure domains and to the coherent rotation of moments in the columns. Fiber response was also investigated as a function of the field direction and angle of incidence, fiber twisting and for strong transverse fields. The results are discussed in terms of the existing models, and a new model is proposed to explain the transerse effect. The structures and operating principles of single- and dual-fiber biased sensors based on the longitudinal effects are presented. Distortions due to overbiasing are accounted for by the pinning and expansion of large-area closure domains with moments tilted by the casting stress. The sensitivity-linearity range product is the same for several bias levels, and a family of sensors was obtained using the same fiber