Electricity: measuring and testing – Magnetic – Magnetic information storage element testing
Patent
1995-03-02
1997-05-13
O'Shea, Sandra L.
Electricity: measuring and testing
Magnetic
Magnetic information storage element testing
324235, G01R 3312, G01N 2776
Patent
active
056296207
ABSTRACT:
In the simplest embodiment of the invention, the apparatus holds the edge of the magnetized film to be measured close to, and above, a linearly biased magnetoresistive (MR) element. Magnetic poles appearing at the magnetic discontinuity at the edge of the film generate a magnetic field which is incident on the MR element, and which results in a measurable change in the element's resistivity. In a preferred embodiment, a pair of MR elements are placed so that they are both linearly biased by a magnet; only one of the MR elements being in close proximity to, and influenced by the magnetic field emanating from the edge of the magnetized film. The second MR element, selected for matched characteristics with the first MR element, is located out of the field of the magnetized film, but still subject to the same temperature environment and field noise as the first MR element. The two MR elements are configured with associated resistors as arms of a Wheatstone bridge so that the common mode fields and thermal drift signals experienced by both MR elements are canceled to the first order, and the output of the bridge is proportional to the change in resistance in the first MR element due only to the field of the magnetized film.
REFERENCES:
patent: 3535622 (1970-10-01), Cannon et al.
patent: 3562635 (1971-02-01), Parker
patent: 4038692 (1977-07-01), Umeda et al.
patent: 4182985 (1980-01-01), DeWolfe et al.
patent: 4213091 (1980-07-01), Cooper
patent: 4276324 (1981-06-01), Pohler et al.
patent: 4603365 (1986-07-01), Nakamura
patent: 4901016 (1990-02-01), Kusatani et al.
patent: 5351005 (1994-09-01), Rouse et al.
IBM Technical Bulletin, vol. 6, No. 8, Jan. 1964 pp. 48-49.
Jeffers Frederick J.
Smith Neil
Eastman Kodak Company
Noval William F.
O'Shea Sandra L.
Phillips Roger C.
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