A magnetic recording medium having a composite magnetic recording
structure comprising the combination of a hard magnetic layer and a
metamagnetic layer that possesses a field induced metamagnetic transition
characteristic at ambient operating temperature. Under an applied
external magnetic field, the metamagnetic layer transitions from an
antiferromagnetic state to a ferromagnetic state, and the magnetic field
induces magnetization of the metamagnetic layer. The hard magnetic
recording layer is magnetically exchange coupled to the magnetized
metamagnetic layer. This results in the softening of the coercivity of
the overall magnetic recording structure and reduction of the required
switching field during data recording. Upon removal of the applied
magnetic field, the metamagnetic layer experiences transition back to an
antiferromagnetic state and the coercivity of the hard magnetic layer is
restored. This restoration allows the written bit to be stored at a high
thermostability ratio and thus, preventing magnetization thermal decay of
the data bit.