Papers by Keyword: Magnetic Head

Abstract: Magnetic recording technologies are continuing to advance toward higher areal densities, driven by the availability of tunneling magnetoresistive (TMR) heads. However, high areal density heads require smaller physical dimensions, and this can render TMR heads more vulnerable to mechanical stresses generated during the lapping process. Although is important to verify the durability of TMR heads against lapping, it is very difficult to perform a crystallographic analysis of the affected layer because of the small dimensions involved. In this study, we attempted to establish an advanced TMR head verification method based on a magnetic performance analysis involving micro-Kerr hysteresis loops and the magnetic noise spectrum. We found that the magnetic performance changed when nanoscale scratches were removed from the lapped surface using ion beam etching. This indicates that the lapping process produces an affected layer which deteriorates the magnetic characteristics of the TMR head. A correlation was also found between the change in magnetic performance and the morphology of lapped surface.

Abstract: In order to reach the deep of a human body, steerable needle is usually used in minimally invasive surgeries. For increasing the steerability and steering accuracy, a novel magnetic articulated needle is proposed in this paper. The proposed needle consists of a magnetic head, articulations, and sections. A magnetic force is generated on the needle head by adding an external magnetic field, which is used to manipulating the needle’s inserting path. The generated magnetic force and the motion of such a needle are analyzed for understanding the steering of the needle. The proposed needle is more easily to be controlled to avoid obstacles in human body while inserting.

Abstract: We investigated the durability of giant magnetoresistive (GMR) heads to nanoscale scratches created during the lapping process. Analysis using high-field transfer curves after deliberate scratching with an atomic force microscope (AFM) identified changes in the magnetization of the head and a reduction in pinning strength, which is a magnetic performance indicator. Additionally, finite element method (FEM) analysis suggested that the overall effects on the GMR head following nanoscale scratching increased with scratch depth.