In:
Journal of Applied Physics, AIP Publishing, Vol. 37, No. 3 ( 1966-03-01), p. 1359-1360
Abstract:
If a magnetic film (the shield) with transverse saturation demagnetizing field Hd and anisotropy field Hk is placed in a transverse field below saturation strength (Hd+Hk), it experiences a net field less than Hk. A second film (the storage film), when placed on top of the first, will experience the same net field. If the anisotropy field of the storage film is much greater than that of the shield, the magnetization of the storage film undergoes a negligible rotation for all applied fields below Hd+Hk. Once the shield has saturated, any further increase in field is applied directly to storage film. The resulting plot of the net field at the storage film versus applied field shows a symmetrical offset threshold of approximate magnitude Hd. Control of the shield geometry provides a means for adjusting this threshold. To investigate the shielding effect, two experiments were performed. The first used a 0.5-in.-wide Supermalloy tape to approximate an ideal shield and measured net field at its center line as a function of field applied with Helmholtz coils at very low frequencies. The second sought to demonstrate the practicality of shielding in a film memory. Both shield and storage medium were thin films of 0.004-in. width driven by pulsed word and digit fields using a technique which eliminated the readout from the shield. The results of both experiments show agreement with the theoretical models proposed in the paper. Possible applications of the shielding technique are to all-magnetic selection in film memories and to creep reduction in conventional word-organized film memories.
Type of Medium:
Online Resource
ISSN:
0021-8979
,
1089-7550
Language:
English
Publisher:
AIP Publishing
Publication Date:
1966
detail.hit.zdb_id:
220641-9
detail.hit.zdb_id:
3112-4
detail.hit.zdb_id:
1476463-5
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