Tunnel magnetoresistive multi-turn sensor

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. In the arrangements described herein, the length of the TMR sensing elements can be significantly reduced and tighter sensor spiral can be achieved, thus reducing the overall size and defectivity of the MT sensor.