Magnetoresistive Permalloy sensors with increased sensitivity

The sensitivity of a magnetoresistive sensor is the principal parameter for most applications. We present a simple graphic analysis method in which sensitivity is considered as a consequence of stability and equilibrium conditions of the magnetization in thin soft magnetic elements with in-plane uniaxial anisotropy. We developed a Permalloy thin film sensor with a barber-pole design whose sensitivity was increased to more than 100 mV/V/kA/m in the easy axis direction. Anisotropy and demagnetizing fields are in the same order as the bias field