Magnetoresistive transducer with canted easy axis

An improved approach to biasing a magnetoresistive head is described which uses two coupled magnetic strips whose easy axes are canted at an optimum angle with respect to the length of the strips. In zero field, the moments of the two strips point in opposite directions and the signal is detected differentially. The canted easy axis and the differential detection combine to minimize second harmonic distortion and the intimate contact between the sensor layers eliminates thermal noise. Both demagnetization field components are externally coupled, which minimizes domain wall formation, thus reducing Barkhausen noise. The bias angle is essentially constant over the strip area which results in enhanced sensitivity. A nonmagnetic conductor strip, which carries the sense current in the opposite direction, is placed between,and insulated from, the two magnetic strips. This serves to cancel the current fields and makes both element resistances independent of sense current. The optimum easy axis angle and sensitivity are expressed in terms of the parameters involved and the analog reproduce performance of an unshielded head is predicted.