Magnetoresistive switching of small permalloy sandwich structures

Abstract

The magnetoresistive (MR) switching behavior of small permalloy/silicon monoxide/permalloy sandwich elements is investigated. A comparison with single layer elements shows that the best MR-switching results are found for the sandwich structures with the smallest dimensions (10×100 μm). A theoretical calculation based on the magnetostatic coupling between the two permalloy layers of the sandwich and on inhomogeneous demagnetizing fields shows good agreement with the experimental results. The formation of magnetic domain configurations other than those found in small single layer elements is illustrated using a ferrofluid observation technique.

Micromagnetic study of the double-layered MR elements

“…Ooyen et al [12] reported that sandwich structured films in which two homogeneous magnetic layers are separated by a nonmagnetic layer can produce a large reduction in magnetostatic energy (demagnetizing field). It was further reported by Berchier et al [13] that this structure indeed leads to a significant reduction in the domain walls, exhibiting a better noise performance in the devices.…”

An investigation of the switching threshold of multilayer thin film magneto-resistive memory elements

“…Bogue has described a novel application for magneto-resistive sensors in detecting wear to prevent expensive breakdown of industrial machinery [20]. Experimental data of magnetoresistive output of a permalloy sandwich structure with the easy axis along the length of the structure has been reported by Berchier et al [21]. The center layer in this report was an insulator, silicon monoxide.…”

A study of magnetoresistivity in multilayer thin film

“…Magnetic properties of sandwich structures have been investigated using the magnetoresistance effect of thin Permalloy films [39][40], As expected, this structure shows strong magnetostatic coupling which decreases the demagnetizing field and improves the switching properties.…”