Patent ID: 6989974

Claim:
A magnetic recording/reproducing apparatus, comprising: a magnetoresistive head including a spin-valve film as a magnetic sensor element for detecting magnetic signals, said spin-valve film having a structure in which an anti-ferromagnetic layer, a pinned layer in which the direction of magnetization is pinned in a predetermined direction by an exchange-coupling magnetic field at work between itself and said anti-ferromagnetic layer, a free layer in which the direction of magnetization changes in accordance with an external magnetic field, and a non-magnetic layer for magnetically isolating said pinned layer and said free layer are layered, wherein magnetic signals are detected from a magnetic recording medium, which includes a tape-shaped non-magnetic substrate and a metal magnetic thin film formed thereon, while in sliding contact, said spin-valve film has a corrosion potential relative to a standard hydrogen electrode of +0.4. [V vs. SHE] or greater when immersed in a NaCl solution of a concentration of 0.1 mol/L, a product Mr·t of residual magnetization Mr and thickness t of said metal magnetic thin film is 4 mA to 20 mA, and said residual magnetization Mr is 160 kA/m to 400 kA/m.