A magnetic layer which is exchange-coupled to an antiferromagnetic layer
and given an exchange bias therefrom is laminated via a non-magnetic layer
on another magnetic layer to form an MR film. The antiferromagnetic layer
(PtMn, PdMn or NiMn) is laminated on a ground layer (Zr, Hf, Zr--Hf,
Zr--Co, Zr--Au, Ni--O, Co--O or Fe--O) so that the antiferromagnetic layer
has a surface of an average roughness of 1-5 .ANG.. A conduction layer is
formed adjacent to the magnetic layer for sensing a magnetic field. The
conduction layer is made of Cu, Ag, Au or an alloy composed of two
selected therefrom. A layer made of Zr, Ta, Zr--O, Ta--O or a mixture
thereof is laminated on the conduction layer. The MR film exhibits a large
resistance variation linearly at near zero magnetic field with an
excellent thermal stability.
