Magnetoresistive spin valve sensor with stepped layers
Patent 5867025 Issued on February 2, 1999. Estimated Expiration Date: 
June 13, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
June 13, 2017. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesMagnetoresistive device and method of preparing the same Patent #: 5680091 InventorsApplicationNo. 836841 filed on 06/13/1997US Classes:324/252, Semiconductor type solid-state or magnetoresistive magnetometers338/32R, Magnetic field or compass (e.g., Hall effect type)360/324.1, Having one film pinned (e.g., spin valve)428/611Having magnetic properties, or preformed fiber orientation coordinate with shapeExaminersPrimary: Snow, Walter E.Attorney, Agent or FirmInternational ClassesG01R 033/09H01F 001/00 H01L 043/00 G11B 005/39 AbstractA magnetoresistive spin valve sensor is described. Such a sensor is also known as a GMR sensor or giant magnetoresistive sensor. The layers (24, 26, 28) of the sensor are mounted on a substrate (20) having steps or terraces on one of its face. The steps or terraces on the substrate's surface cooperate with one or more of the ferromagnetic layers (24, 28) of the sensor to determine the layers' magnetic properties. Specifically, the thickness of one or more of the sensor's layers can be set above or below a critical thickness which determines whether the easy direction of uniaxial magnetization of a layer of that particular material is fixed or "pinned". If pinned, the layer has a high coercive field. Thus, the new device avoids a biasing layer to pin any of the magnetic layers. Preferably the easy axes of the first two ferromagnetic layers (24, 28) are set at 90° to one another in the zero applied field condition by appropriate choice of layer thickness. A method for manufacturing and several fields of use of the sensor are also disclosed. | |
