Magnetoresistive transducer with four-lead contact
First Claim
1. A thin film magnetic head comprising:
- a magnetoresistive read transducer having first and second contact regions spaced by an active region;
first and second electrical leads connected respectively to said first and second contact regions for directing bias current to said transducer; and
third and fourth electrical leads connected respectively to said first and second contact regions for simultaneously detecting magnetic flux representative of recorded signals and directing the detected signal to an output circuit, wherein said first and third electrical leads are electrically connected by a first conductive feedthrough at said first contact region, said first and third electrical leads being dielectrically separated from each other by a first insulating layer at regions other than said first contact region.
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Abstract
A magnetic head includes a magnetoresistive read transducer which comprises a central active region and two end regions. Bias current leads are connected respectively to end regions for current biasing of the transducer. Signal sensing leads is also are connected respectively to end regions for directing sensed voltage to a signal amplifier. The bias current and the sensed signal assume separate electrical paths. The current crowding effect in the bias current path does not affect the signal sensing path. Thus the transducer can sense signal with improved sensitivity and high signal-to-noise ratio. In one embodiment, at each end region, the bias current lead and the signal sensing lead are coplanar and are bifurcated to effectuate separate electrical paths. In another embodiment, the signal sensing lead and the bias current lead are electrically connected together via an electrical feedthrough at each end region, but are dielectrically separated by an insulating layer at other regions.
69 Citations
15 Claims
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1. A thin film magnetic head comprising:
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a magnetoresistive read transducer having first and second contact regions spaced by an active region; first and second electrical leads connected respectively to said first and second contact regions for directing bias current to said transducer; and third and fourth electrical leads connected respectively to said first and second contact regions for simultaneously detecting magnetic flux representative of recorded signals and directing the detected signal to an output circuit, wherein said first and third electrical leads are electrically connected by a first conductive feedthrough at said first contact region, said first and third electrical leads being dielectrically separated from each other by a first insulating layer at regions other than said first contact region. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A thin film magnetic head for reading magnetically recorded signals and for transducing changes in magnetic flux representative of information recorded on a magnetic medium to electrical signals comprising:
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a read transducer including first and second contact regions spaced by an active region, said active region varying in electrical resistivity in response to changes in magnetic flux; first and second electrical leads in contact with and connected respectively to said first and second contact regions; and third and fourth electrical leads in contact with and connected respectively to said first and second contact regions; so that when an electrical current passes through said transducer via said first and second electrical leads, said active region of said transducer varies in resistivity in response to changes in magnetic flux sensed by said magnetic head, and a varying signal is produced at said transducer that passes through said third and fourth electrical leads as electrical signals representative of recorded data signals. - View Dependent Claims (9, 10)
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11. A thin film magnetic head for reading magnetically recorded signals and for transducing changes in magnetic flux representative of information recorded on a magnetic medium to electrical signals comprising:
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a read transducer including first and second contact regions spaced by an active region, said active region varying in electrical resistivity in response to changes in magnetic flux; first and second electrical leads in contact with and connected respectively to said first and second contact regions; and third and fourth electrical leads in contact with and connected respectively to said first and second contact regions; so that when an electrical current passes through said transducer via said first and second electrical leads, said active region of said transducer varies in resistivity in response to changes in magnetic flux sensed by said magnetic head, and a varying signal is produced at said transducer that passes through said third and fourth electrical leads as electrical signals representative of recorded data signals;
wherein said first, second, third and fourth electrical leads are coplanar;wherein said first and third electrical leads are electrically connected by a conductive feedthrough at said first contact region, said first and third electrical leads being dielectrically separated by a first insulating layer at regions other than said first contact region; wherein said second and fourth electrical leads are electrically connected by another conductive feedthrough at said second contact region, said second and fourth electrical leads being dielectrically separated by a second insulating layer at regions other than said second contact region. - View Dependent Claims (12, 13, 14, 15)
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Specification