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In this article, we describe the fabrication and characterization of a spin valve (SV) magnetoresistive (MR) sensor, located in the gap of two magnetically soft flux guides (FGs) that enhance the sensor magnetic field sensitivity, while keeping in the sensor a quasilinear Barkhausen-noise-free response. Top pinned SV sensors were fabricated into stripes, having lengths of 100 μm and widths of 2 and 3 μm, by optical lithography and ion-milling etching. The FGs consisted of poles and yokes of an amorphous alloy of Co88.4Zr3.3Nb8.3, prepared by physical vapor deposition and were lithographically defined by a lift-off process. The SV sensor MR responses to applied uniform magnetic fields Ha, when either isolated or located in the gap of two types of FGs, were characterized in terms of the saturation field, coercive force, and sensitivity. The impact of the FG geometry in the magnetic field amplification and sensor response characteristics were studied. Magnetic force microscopy analysis was performed to identify the presence of multidomain states in the FGs and of a remanent field in their gap. SV sensors in the gap of FGs using long poles and having a sensing area of 1000 μm2 exhibit a linear sensitivity of 50 mV/Oe in the field range of a couple of oersteds. The SV sensor in the gap of magnetically soft FGs exhibits enhanced hysteresis, characterized by a coercive force of approximately 1 Oe. Two schemes are proposed to reduce the hysteresis in the sensor response. [ABSTRACT FROM AUTHOR]

Presents a study which examined magnetization reversal processes in sputtered antiferromagnetically coupled multilayers using a Monte Carlo simulation. Details of research on magnetization processes in antiferromagnetically coupled magnetic multilayers; Experimental method used; Details on the Monte Carlo simulation used.

Presents a study that investigated antiferromagnetic exchange and enhanced magnetoresistance in glass/iron[sub50 Å]/cobalt[sub11 Å]/ copper[subtcopper]/cobalt[sub11 Å]/ copper[sub1 Å] structures. Experimental method; Results.

Presents information on a study which investigated the magnetothermopower of antiferromagnetically coupled cobalt-rhenium superlattices. Experimental procedure; Results; Discussion.

Giant magnetoresistive (GMR) sensors can have their field sensitivity enhanced by many fold if located in the gap of two magnetically soft flux-guides (FG). In this paper, we present spin valve (SV) sensors, with saturation fields of less than 3 Oe and high linearity characterized by coercive forces of less than 0.5 Oe. FG require magnetically soft thin films with thicknesses in the range of 100-500 nm. In previous work, we prepared single-layer (SL) films of amorphous Co[sub90 .7] (Zr-Nb)[sub9.3] that exhibited stripe domains (SD) when patterned into FG, causing Barkhausen noise and complete lost of linearity in the SV sensors response. In this article, single layer films of an amorphous alloy of Co[sub88.4] Zr[sub3.3] Nb[sub8 .3], patterned into flux guides, do not exhibit SD but well-behaved closure domains. Nevertheless, these induce hysteresis in the sensors response, characterized by a coercive force of 0.7 Oe. This hypothesis is corroborated by focused beam magneto-optic Kerr effect (MOKE) magnetometry, performed in the poles region the CZN FG. By contrast, FG integrating instead multilayer (ML) thin films consisting of ferromagnetic layers of permalloy weakly antiferromagnetically (AF) coupled through Ru interlayers cause a strong reduction of hysteresis in the SV sensors response. The sensors in the gap of AF coupled (NiFeIRu)xn FG, exhibit saturation fields of about 2 Oe and coercive forces of 0.3 Oe, despite the fact that the isolated sensors exhibit coercive forces of 2 Oe. [ABSTRACT FROM AUTHOR]