Tsann Lin

Design, fabrication and testing of spin-valve read heads for high density recording

Spin-valve sensors of the type NiFe/Cu/Co have been designed for optimal biasing behavior and successfully incorporated into a gigabit-type shielded read head configuration with a read trackwidth of 2 /spl mu/m, a read gap of 0.25 /spl mu/m, and a MR sensor height of 1 /spl mu/m. The spin-valve sensor had a structure of 100 /spl Aring/ NiFe/25 /spl Aring/ Cu/22 /spl Aring/ Co/110 /spl Aring/ FeMn, and yielded a net spin-valve coefficient of /spl sim/3.5% at the completion of head processing. Uniform field testing of the read heads after wafer fabrication and lapping showed quiet and stable spin-valve response with near optimal bias performance. Recording tests of the read heads at a head-disk clearance of 1.5 /spl mu/m showed linear, non-saturated signal response on a media with an areal moment as high as 1.25 memu/cm/sup 2/, yielding reasonably symmetrical signals with peak-to-peak amplitudes ranging from /spl sim/750 /spl mu/V//spl mu/m to as high as /spl sim/1000 /spl mu/V//spl mu/m of read trackwidth. Linear density rolloffs and microtrack profiles have also been studied, and results showed behaviors closely agreeing with design targets for high density recording operations. >

Design, fabrication and performance of spin-valve read heads for magnetic recording applications

Since the early 1990s, the introduction of dual-element recording heads with inductive write elements and magnetoresistive (MR) read elements has almost doubled the rate of areal density improvements for hard-disk-drive data storage products. In the past several years, prospects of even more rapid performance improvements have been made possible by the discovery and development of sensors based on the giant magnetoresistance (GMR) effect, also known as the spin-valve effect, for a particular class of sensor configurations. In this paper, we explore the potentials as well as challenges of spin-valve sensors as magnetic recording read heads. We first examine the data rate and areal density potentials of large read-back signals resulting from increases in the MR coefficient. We then discuss associated magnetic sensor performance, including linearity and noise suppression. Finally, we study in detail the magnetic and recording performance of a spin-valve read head designed for 1-Gbl/in. 2 density performance.