Magnetoresistive response of small permalloy features

We have systematically studied the character and variations of Barkhausen noise in a variety of micron size magnetoresistive sensors. From domain observations, we have revealed the basic micromagnetic process involved and demonstrated the central role played by Neel wall structures and their instabilities in Barkhausen noise. A small amount of easy axis field is effective in producing rotational response and hence quiet magnetoresistive outputs.