Provided is a magnetic reproducing apparatus capable of controlling a
magnetic domain of a free layer, and obtaining a sufficient reproduction
output even if the size of an MR device is reduced. The MR device is
formed so as to have a laminate structure in which a semi-hard magnetic
layer and a first ferromagnetic layer (free layer) are exchange-coupled
to each other through a non-magnetic exchange coupling layer. Unlike an
abutted junction structure using a hard magnetic layer, the distribution
of a magnetic bias applied from the semi-hard magnetic layer to the first
ferromagnetic layer becomes uniform, thereby the first ferromagnetic
layer is brought into a single magnetic domain state. Moreover, the
semi-hard magnetic layer has a moderate coercive force lying halfway
between soft magnetism and hard magnetism, so the magnetization direction
of the first ferromagnetic layer is not fixed. Therefore, the
magnetization direction of the first ferromagnetic layer can be easily
rotated, thereby a magnetoresistive ratio can be secured, so even if the
size of the MR device is reduced, a sufficient reproduction output can be
obtained.