Robert Boschgmbh

Ulrich May

Henrik Siegle

Ingo Herrmann

Paul Farber

Peter Schmollngruber

Hartmut Kittel

Christian Bauer

Stefan Grosse

Maik Rabe

Richard Braak

Rainer Feuerfeil

Birgit Vogelgesang

Gernot Repphun

Andrew Johnson

Michael Fraune

Leni Onuseit

Martin Vincon

The invention relates to a method for carrying out a test and measuring method on a flat test specimen (), wherein a mechanical load is introduced into a test specimen surface () by means of a rotating engraving head () of an engraving device (), wherein the engraving head () penetrates with a defined contact pressure at least into a layer system () applied to the test specimen (), wherein the rotating engraving head () is moved along the test specimen surface () and relative to the test specimen () in order to create at least one engraving () on the test specimen surface () by plastic deformations and/or brittle chipping of the layer system (), and wherein the at least one engraving () introduced into the test specimen surface () is measured using a photo-optical method in order to evaluate layer adhesion of the layer system () to the main body (). The invention also relates to an engraving device () for carrying out such a method.

Engraving device and method for creating and measuring stress corrosion cracking on a flat coated test specimen

A magnetic sensor system () is provided that contains sensor elements () that are sensitive to magnetic fields, the electrical properties of said sensor elements being modifiable according to a magnetic field that can be influenced by a mobile, passive transmitter element (). The magnetic sensor system () includes two sensor elements () in a gradiometer system, each of which is assigned to one of two permanent magnets () having a predetermined separation. In terms of their dimensions, separation and position relative to the sensor elements (), the permanent magnets () are located such that the offset of the output signal of the sensor elements () is minimized in the gradiometer system.

Magnetic sensor system

A magnetoresistive layer system, in an environment of a magnetoresistive layer stack that works particularly on the basis of the GMR effect or the AMR effect, a layer array being provided which generates a magnetic field which acts upon the magnetoresistive layer stack, and the layer array having at least one hard magnetic layer and at least one soft magnetic layer. Furthermore, a sensor element, particularly for the detection of magnetic fields with respect to their strength and/or direction, having such a layer system.

Magnetoresistive layer system and sensor element having this layer system

A GMR sensor element is proposed, having a rotationally symmetrical positioning of especially eight GMR resistor elements which are connected to each other to form two Wheatstone's full bridges. This GMR sensor element is especially suitable for use in an angle sensor for the detection of the absolute position of the camshaft or the crankshaft in a motor vehicle, particularly in the case of a camshaft-free engine having electrical or electrohydraulic valve timing, of a motor position of an electrically commutated motor, or of detection of a windshield wiper position, or in the steering angle sensor system in motor vehicles.

GMR sensor element and its use

A magnetoresistive sensor element is provided, having a magnetoresistive layer system which, in top view, is at least regionally striated. The sensor element operates on the basis of the GMR effect and is constructed according to the spin valve principle, the striated layer system featuring a reference layer having a direction of magnetization substantially uninfluenced by a direction of an outer magnetic field acting on it. During operation, the sensor element provides a measuring signal which changes as a function of a measurement angle between the component of the field strength of the outer magnetic field lying in the plane of the layer system, and the direction of magnetization, and from which this measurement angle is able to be ascertained. In addition, observed in a top view of the striated layer system, the angle between the direction of magnetization in the absence of the outer magnetic field and the longitudinal direction of the striated layer system is set in such a way that in response to an influence of the outer magnetic field having a defined field strength, which is selected from a predefined work interval, the angle error of the layer system, as a function of this angle and the field strength, is minimal.

Magnetoresistive sensor element and method for reducing the angular error of a magnetoresistive sensor element

A method of adjusting or locally modifying the direction of magnetization of a ferromagnetic layer in a magnetoresistive layer system using a heat stamp is described, the ferromagnetic layer being stabilized over an antiferromagnetic layer. The antiferromagnetic layer is heated, using a heat stamp, over a threshold temperature, above which the influence of this layer on the direction of magnetization of the adjacent ferromagnetic layer disappears; subsequently, the ferromagnetic layer is exposed to an external magnetic field of a predefined direction, and finally the antiferromagnetic layer is cooled again below the threshold temperature. In addition, a heat stamp having a base body and a heatable stamp structure connected to the base body and matching the dimensions of or similar to the magnetoresistive layer system is described. The heat stamp and the method described are suitable in particular for manufacturing a magnetoresistive layer system operating by the spin valve principle, which has a plurality of magnetoresistive layer systems having at least partially different resulting directions of magnetization in the particular layers, the magnetoresistive layer systems being interconnected in the form of a Wheatstone bridge in particular.

Method of adjusting or locally modifying a magnetization in a layer of a magnetoresistive layer system, heat stamp for heating the magnetoresistive layer system, and use of same

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Stuttgart, Germany

Ulrich May