Abstract
The shapes of magnetoresistive (MR) elements which suppress Barkhausen noise originating from domain activity were studied. We particularly attempted to suppress the Barkhausen noise by using a flux closure scheme which consists of shaping the MR element into a “picture-frame” geometry with a small gap (called a Closed Type MR element).
We investigated MR response of the CTMR element and compared it with the conventional MR element shaped stripe. In the stripe element, when the length was shorter than 100μm, Barkhausen noise was observed throughout the region of the sensor by a Kerr-effect microscope. On the contrary, the CTMR element exhibited quiet response in most of the sensor region. We found that an MR head with track pitch of less than 40μm could be realized, based on the design of the optimum sensor region.
We fabricated Yoke Type MR heads which incorporated the CTMR element or the stripe element in the magnetic yoke, and evaluated the difference in the reproducing characteristics between these elements. The results showed that the noise level was 10dB lower for the CTMR element than for the stripe element and higher harmonics distortion decreased.
