Abstract: The present disclosure provides tunnel magnetoresistive (TMR) multi-turn (MT) sensors with improved sensor read-out and methods of manufacturing said sensors. In some examples, the TMR sensing elements of the MT sensor are each provided with two or more electrical contacts for performing current-in-plane tunnelling measurements. The two or more electrical contacts may be provided above or below the TMR sensing elements. In further examples, one or more read-out pillars formed from TMR sensing material may be provided, the read-out pillars being electrically connected to one or more TMR sensing elements. The read-out pillars are configured such that the resistance observed in the read-out pillars is negligible or near-negligible relative to that observed in the TMR sensing elements, such that the measured output signal only reflects the change in resistance experience by the TMR sensing elements in the presence of an externally rotating magnetic field.

Abstract: The present disclosure provides tunnel magnetoresistive (TMR) multi-turn (MT) sensors with improved sensor read-out and methods of manufacturing said sensors. In some examples, the TMR sensing elements of the MT sensor are each provided with two or more electrical contacts for performing current-in-plane tunnelling measurements. The two or more electrical contacts may be provided above or below the TMR sensing elements. In further examples, one or more read-out pillars formed from TMR sensing material may be provided, the read-out pillars being electrically connected to one or more TMR sensing elements. The read-out pillars are configured such that the resistance observed in the read-out pillars is negligible or near-negligible relative to that observed in the TMR sensing elements, such that the measured output signal only reflects the change in resistance experience by the TMR sensing elements in the presence of an externally rotating magnetic field.

Abstract: The techniques described are applicable to closed-loop magnetic multi-turn sensors including giant magnetoresistance (GMR-MT) sensors as well as tunnel magnetoresistive (TMR) multi-turn sensors. Techniques, e.g., lithography techniques, are described to form crossings so that a distortion of an ideal shape is reduced or minimized. Another aspect describes techniques to modify the material thickness and/or magnetic properties in such an area of the crossing. Yet another aspect describes techniques to locally weaken the applied field in the area of the crossing to prevent nucleation events in this area. The techniques described are applicable to closed-loop magnetic multi-turn sensors including giant magnetoresistance (GMR-MT) sensors as well as tunnel magnetoresistive (TMR) multi-turn sensors.

Abstract: A giant magnetoresistance (GMR) element is provided for use in a magnetic multi-turn sensor in which the free layer, that is, the layer that changes its magnetization direction in response to an external magnetic field so as to provide a resistance change, is thick enough to provide good shape anisotropy without exhibiting an AMR effect. To achieve this, at least a portion of the free layer comprises a plurality of layers of at least two different materials, specifically, a plurality of layers of at least a first material that is ferromagnetic and a plurality of layers of at least a second material that is known not to exhibit an AMR effect and that does not interfere with the GMR effect of the layers of ferromagnetic material.