US 4,881,143 A · Compensated magneto-resistive read head

Abstract

A read/write head for a hard disk provides both a magneto-resistive read function and an inductive write function in a common gap. The inductive write function is provided by a current carrying coil which is magnetically coupled to top and bottom shields or pole tips which in turn induce the magnetic fields required for writing on the disk. Mutually biasing magneto-resistive read sensor are located between the shields, which serve to improve the resolution of the read function. During a read operation, read/write circuitry maintains a current in the coil which cancels, at least partially, magnetic fields induced by sensing and bias currents in the magneto-resistive heads which might other perturb information stored in the medium. This arrangement provides a read/write head with improved read/write resolution as required by emerging high density storage media in compact formats.

Claims9

Dependent claims

A device comprising:

read means for modulating a voltage drop imposed on an electrical read current to provide a signal as a function of flux levels stored in a magnetic medium moving relative to said read means, said read means including input means for receiving said read current, said read means including output means for transmitting said signal;
shield means for isolating said read means from magnetic fields from sources other than a portion of said magnetic medium at a predetermined location relative to said read means, said shield means being positioned with respect to said read means so that said read current induces a magnetic field in said shield means;
and
cancellation means for substantially cancelling said magnetic field in said shield means.

1 more element

Dependencies are inferred from the claim text.

Compensated magneto-resistive read head

Life of this patent

Compensated magneto-resistive read head

Life of this patent

Abstract

Claims9