MAGNETIC SENSOR, MAGNETIC HEAD AND MAGNETIC DISK DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a magnetic sensor which can realize MR ratio of at least 30%. SOLUTION: This magnetic sensor has a ferromagnetic tunnel junction unit which includes a first ferromagnetic metal layer and a second ferromagnetic metal layer formed thereon through an insulating barrier layer. At least either of the first and second metal layers is formed of a CoFe alloy containing Fe at a composition ratio of 25 to 51 at.%.