A thin magnetic film shift register

A thin magnetic film shift register can be operated with high reliability by providing the high coercive force at the edges of the channel; which can be realized by the following three methods. 1) A Permalloy is evaporated onto a substrate masked by a nonmagnetic metal pattern which is placed a very small distance from the substrate. 2) As complicated channels cannot be constructed with method 1), double layers, which consist of an aluminum and a copper, are utilized. After evaporation of a Permalloy onto the entire double layer, an aluminum and a copper are etched away in caustic soda. 3) As the coercive force of the Permalloy film with the aluminum underlayer is high, the edges of the channels are made using double layer construction. An operating speed of ∼1 MHz is obtained and maximum storage is about 2000 bit/cm².