| 摘要 |
1391150 Magnetic heads INTERNATIONAL BUSINESS MACHINES CORP 12 Oct 1973 [30 Nov 1972] 47709/73 Heading G5R [Also in Division H3] Decrease of sensitivity due to oxidization of a magnetoresistive thin film magnetic bubble sensor or magnetic tape reading head is prevented by an overlay of Al 2 O 3 or Si 3 N 4 . The magnetoresistive material may be permalloy, or an alloy of Ni-Fe, Ni-Fe-Co, Ni-Co or Fe-Co, and have a thickness of between 200Š and 1000Š. The overlay may be of twice this thickness. As applied to sensing magnetic bubbles 4, Fig. 1, in a magnetic plate 2, the sensor consists of a permalloy element 10 having an easy axis of magnetization in the direction of current flow from a source 12 through the element. The presence of a magnetic bubble changes the element resistance which is detected by the change of voltage across the source. A layer of a dielectric material S and a sputtered layer 18 of Al 2 O 3 or Si 3 N 4 extend over the magnetic plate and the magnetoresistive element. Similar layers are applied over the reading head 20, Fig. 2, of a moving magnetic tape 22, the magnetoresistive sensor 10 being similar to that shown in Fig. 1. |
