Read Rite Corporation

International Business Machines Corporation

Erich P Valstyn

Daniel A Nepela

Robert D Hempstead

David A Thompson

Peter G Bischoff

Swie-In Tan

Charles R Bond

Norman G Ainslie

Sol Krongelb

Edgar M Williams

Derek Jan Kroes

Shih-Cheng Cheng

A thin film read-write magnetic head useful in a tape apparatus includes a magnetic circuit consisting of two thin film magnetic layers which form a magnetic yoke that is divided into three closely spaced sections, the central section of at least one of the magnetic layers containing an interspace in which a flux sensing element, such as a magnetoresistive device or Hall effect device, is located. The three section yoke forms a continuous magnetic circuit, except for the transducing gap, which circuit consists of three sections corresponding to the three sections of the yoke. The total gap width determines the width of the data track being recorded. During the write mode, a magnetic valve including an electrical conductor provides a shunt path to bypass the flux sensing means so that all three sections of the head operate for recording. During the read mode, only the central yoke section and its transducing gap portion sense the data signal recorded on the magnetic tape, and the read element detects the sensed signal. A saturation current is directed to the valve conductor during the read mode so that the shunt path is open, thereby allowing the flux sensing means to operate and sense the readout signal.

Magnetic tape head with flux sensing element

A magnetoreristive head assembly has a magnetic bias level control for continuous compensation of thermal, stray field and stress fluctuations, as well as other types of fluctuations. The magnetoresistive head assembly includes a magnetoresistive element for sensing signals recorded on a magnetic medium, and for generating electrical signals corresponding to the recorded signals. A bias current balancing circuit has an input connected to the magnetoresistive element for sensing the electrical signals and for generating a correction bias current therefrom. A feedback correction circuit converts the correction bias current into a correction magnetic bias field and applies the field to the magnetoresistive element to limit the shifting of a current bias point of the magnetoresistive element and to compensate for bias fluctuations.

Magnetoresistive head with magnetic bias level control

A thin film magnetic head is fabricated with a multiplicity of magnetic yokes that interact effectively with an electrical coil. The magnetic P1 and P2 pole sections of the yoke are very narrow and form closely spaced envelopes about the coil. The multiple yokes are inductively linked to the coil so as to provide an increased number of flux interactions for a given length of coil turn. With this magnetic head design, signal output is increased, thermal noise is reduced, and the signal-to-noise ratio is effectively improved.

Thin film magnetic heads with multiple yokes

A thin film read-write magnetic head includes first and second adjacent magnetic layers forming a magnetic circuit path with a transducing gap, a flux sensing element disposed in the plane of one of the magnetic layers, at least one magnetic shunt valve member disposed around the flux sensing element, the valve member being disposed in the same plane as the one of the magnetic layers in which the sensing element is disposed. A conductor is electrically connected to the flux sensing member and magnetically coupled to the shunt valve member to apply a magnetic field to the shunt valve member to magnetically control the shunt valve member.

Integrated yoke magnetoresistive transducer with magnetic shunt

A read/write head includes a dual element MR sensor and a superimposed inductive head. In an implementation of the invention, the MR sensor structure includes two spaced magnetoresistive (MR) elements on which antiferromagnetic (AFe) thin films, preferably of iron manganese, are deposited. The AFe thin films act as exchange bias layers with the MR elements, biasing the MR layers in opposite directions and perpendicular to the surface of a magnetic medium. Recorded magnetic signals are sensed differentially and the output signal is characterized by increased amplitude and improved signal-to-noise ratio.

Dual element magnetoresistive sensing head

A thin film read-write magnetic head includes a write inductive section having a magnetic circuit consisting of thin film magnetic layers and a read flux sensing element, such as a magnetoresistive device or Hall effect device, located in a gap in the magnetic circuit. During the write mode, a magnetic valve including an electrical conductor provides a shunt path to bypass the flux sensing element. During the read mode, a saturation current is directed to the valve conductor so that the shunt path is open, thereby allowing the flux sensing element to sense the readout signal.

Read-write magnetic head with flux sensing read element

In thin film magnetic transducers, e.g., inductive or magnetoresistive recording heads, at least a pair of layers of a ferromagnetic material and an antiferromagnetic material are deposited upon one another and exchange coupled to retain a unidirectional bias in the plane of the ferromagnetic material. When multiple pairs of layers are used, they are separated by layers of nonmagnetic material. In some cases, successive pairs of layers of material with unidirectional bias have their directions of bias pointing in opposite directions. The domain walls in the layers of material are minimized by this technique.

Antiferromagnetic-ferromagnetic exchange bias films

Iron-silicon is sputtered onto a substrate to be used for a magnetic recording head from a target containing 4% to 7% of silicon with a substrate bias between -2.5 and -60 volts, anode-cathode spacing of about 1/2 to about 2 inches, a deposition rate of greater than 150A/min, a substrate temperature above 250.degree. C, an argon pressure above 10 microns, and a single film thickness greater than 0.4 micron, a laminated film thickness greater than 0.05 micron, and R.F. input power above 8 watts/in.sup.2.

Growing community of inventors

Los Gatos, CA, United States of America

Erich P Valstyn