Nec Corporation

Tdk Corporation

Nec Laboratories America, Inc.

Tao Zhou

Stuart A Solin

Daniel R Hines

Kazuhiko Hayashi

Keishi Ohashi

Tineke Thio

Jonathan E Moussa

Lakshminarayanapuram Ramdas Ram-Mohan

John M Sullivan, Jr

This invention relates to a method and system for finite element modeling of enhanced magnetoresistance in thin film semiconductors containing at least one metallic inclusion therein. The method and system utilizes finite element analysis techniques as a function of the applied magnetic field and the geometry of the device for comparing the device characteristics with predetermined qualities and modifying the device to achieve a correlation between the device characteristics and the predetermined qualities.

Method and system for finite element modeling and simulation of enhanced magnetoresistance in thin film semiconductors with metallic inclusions

A magnetoresistive sensor includes a magnetoresistive element and equipment which generates a magnetic field in the magnetoresistive element thereby inducing a biasing magnetic field in the element, where the magnetoresistive element comprises a high electron mobility semiconductor and electrodes which are connected to the semiconductor. If it is an insulator, the equipment, which generates the biasing magnetic field and supplies it to the magnetoresistive element, may contact directly to the magnetoresistive element. If it is a conductor, an insulating separation layer must be set between the equipment and the element. A magnetoresistive element is representatively Corbino disk type or a bar type magnetoresistive element. Another candidate of the magnetoresistive element is an element consisting of a high electron mobility semiconductor, a pair of electrodes which make a current path in the high electron mobility semiconductor, and another pair of electrodes to detect the induced voltage by the current.

Magnetoresistive sensor, magnetoresistive head, and magnetic recording/reproducing apparatus

A symmetric van der Pauw disk of homogeneous nonmagnetic semiconductor material, such as indium antimonide, with an embedded concentric conducting material inhomogeneity, such as gold, exhits room temperature geometric extraordinary magnetoresistance (EMR) as high as 100%, 9,100% and 750,000% at magnetic fields of 0.05, 0.25 and 4.0 Tesla, respectively. Moreover, for inhomogeneities of sufficiently large cross section relative to that of the surrounding semiconductor material, the resistance of the disk is field-independent up to an onset field above which the resistance increases rapidly. These results can be understood in terms of the field-dependent deflection of current around the inhomogeneity. The EMR exhibited by a composite van der Pauw sensor comprising a semiconductor having an embedded metallic inhomogeneity or internal shunt can be obtained from electrically equivalent externally shunted structures, such as rectangular plates including an external conductive shunt element which is simple to manufacture in the mesoscopic sizes required for important magnetic sensor applications. For example, a bilinear conformal mapping is used to transform a circular composite van der Pauw disk sensor having an embedded conducting inhomogeneity into a corresponding externally shunted rectangular plate structure. The result is an EMR sensor that can be realized in very simple structures which facilitate fabrication in mesoscopic dimensions important for many magnetic sensor applications.

Extraordinary magnetoresistance at room temperature in inhomogeneous narrow-gap semiconductors

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Plainsboro, NJ, United States of America

Tao Zhou