Antiferromagnetically coupled magnetic media layers for thermally stable high-density recording

We describe a magnetic recording media composed of antiferromagnetically co upled (AFC) magnetic recording layers as an approach to extend areal densit ies of longitudinal media beyond the predicted superparamagnetic limit. The recording medium is made up of two ferromagnetic layers separated by a non magnetic layer whose thickness is tuned to couple the layers antiferromagne tically. For such a structure, the effective areal moment density (Mrt) of the composite structure is the difference between the ferromagnetic layers allowing the effective magnetic thickness to scale independently of the phy sical thickness of the media. Experimental realizations of AFC media demons trate that thermally stable, low-Mrt media suitable for high-density record ing can be achieved. (C) 2000 American Institute of Physics. [S0003-6951(00 )02449-9].