HYDROXYALKYLATING AGENT, ITS PREPARATION, AND METHOD OF USING IT

摘要

PURPOSE:To form easily the track width with high accuracy for a magnetic head of a multi-channel tape recorder by forming a lower magnetic layer with the 1st magnetic layer which is filled into a groove formed on a nonmagnetic insulated substrate and the 2nd magnetic layer formed on the 1st magnetic layer. CONSTITUTION:A groove 10 is formed to a nonmagnetic insulated substrate 1, and a magnetic matter is filled into the groove 10 to obtain the 1st magnetic layer 12. The 2nd magnetic layer 13 is formed on the layer 12. Both layers 12 and 13 form a lower magnetic layer having about 10mum thickness. The layer 13 has about 0.5-5mum thickness and the width slightly larger than the track width. This width is controlled to the desired track width by patterning. With such an order of thickness, the high accuracy is secured for the mask of ion etching. This secures the patterning with high accuracy of about + or -2mum.