Role of a Paramagnetic Amorphous CoZr Seed Layer in CoCrPt/Ti Perpendicular Recording Media

Abstract

A fresh CoZr45 paramagnetic amorphous layer of 20 nm thickness is introduced as a seed layer prior to the Ti underlayer deposition on glass substrate in CoCrPt/Ti perpendicular recording media. By the fresh layer introduction, the thickness of Ti underlayer could be reduced to 100 Angstrom to obtain good perpendicular magnetic properties. The cause of this reduction of the critical Ti underlayer thickness is the formation of a more smooth and absorbed impurity free surface by the CoZr layer deposition. This ensures better aligned and finer Ti grain formation at an early stage. Details of the improvements of magnetic properties are discussed. In the second half, we are reporting high K-u behaviors of the CoCrPt/Ti films when the magnetic layers are thinner than 200 Angstrom. The high K-u behavior was associated with the (10.0) lattice expansion of the Co alloy to maintain coherency with (10.0) lattice of the Ti film at the interfaces. These will be discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)68308-6].