Patent ID: 6903908

Claim:
A magnetoresistive effect sensor using a shielded-type magnetoresistive effect element comprising: a magnetoresistive effect film above a lower shield layer, said film comprising a basic configuration that is a combination of a free layer, a barrier layer, and a fixed layer, wherein either said barrier layer is formed on said free layer, and said fixed layer is formed on said barrier layer, or said barrier layer is formed on said fixed layer, and said free layer is formed on said barrier layer, said barrier layer inheriting a roughness of said lower shield layer, wherein a sensing current flows substantially perpendicularly with respect to said magnetoresistive effect film, and wherein a microcrystalline material is used in said lower shield layer so as to smooth said lower shield layer, thereby increasing the smoothness of said barrier layer, wherein said lower shield layer comprises a crystal grain diameter of 6.2 nm or smaller.