DOMAIN STUDIES OF ELECTROPLATED HIGH MOMENT CoFe AND Ni_(45)Fe_(55) ON TEST STRUCTURES

摘要

Magnetic properties of high moment magnetic materials for write head applications were measured for various geometries and anneal conditions. CoFe and Ni_(45)Fe_(55) were electroplated on different test structures with 3-D topography as well as on flat surfaces. Stripes of magnetic material with different width ranging from 5 μm to 50μm are formed using a photo lithographic process. The resist thickness is 3μm and the seed layer was 800 A Ni_(45)Fe_(55) sputtered onto 47mmx47mm glass substrates. The thickness of the electroplated CoFe is between 0.8 urn and 1.8 μm and the electroplated Ni_(45)Fe_(55) is approximately 1.2μm thick. Both B-H loops and domain imaging confirm that the easy axis of the films switches to a direction parallel to the stripes after plating although a magnetic field of 700-1200 Gauss was applied perpendicular to the stripe direction during plating. Another design consists of two layers of photo resist stripes with 20 μm width. These two layers of photo resist stripes are oriented perpendicular to each other. A Ni_(45)Fe_(55) seed layer was sputtered between these layers to provide a conductive surface for electroplating. Domain studies reveal that the preferred transverse domain orientation can be achieved by optimizing the hard-bake conditions for the first layer of photo resist, and for different high moment materials, these conditions need to be optimized individually. This study has potential applications for the domain control in the yoke of write heads for high density and high data rate magnetic recording.