Bicrystal advanced thin-film media for high density recording

A new type of thin-film recording media with advanced microstructure: the bicrystal film, has been studied experimentally. The easy axes of the bicrystal films are oriented along two specified orthogonal directions in the film plane. In this study, an LiF single crystal substrate with (100) orientation is utilized to obtain the Cr monocrystal underlayer with (100) orientation, and on top of the (100)Cr underlayer the CoCrTa with (112̄0) texture was grown epitaxially. X-ray and transmission electron microscopy (TEM) diffraction studies confirm the fabricated thin-film media has the bicrystal microstructure. The magnetic properties of the bicrystal films have demonstrated very high coercivity (H_C∼3000 Oe) and coercive and remanent squareness (S*∼0.9, S∼0.9), all desired for high areal density magnetic recording. The in-plane hysteresis loops of the fabricated films show fourfold symmetry which is the characteristic of the bicrystal microstructure. The effects of Cr underlayer thickness on the magnetic properties of the bicrystal film has also been studied.