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-Gb/in.2 density performance.