MAGNETIC RECORDING APPARATUS HAVING CIRCUITS WITH DIFFERING TUNNEL VALVE SENSORS AND ABOUT THE SAME RESISTANCE

• US 20180366148A1
• Filed: 01/11/2018
• Published: 12/20/2018
• Est. Priority Date: 06/14/2017
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Biskeborn, Robert G., Fontana, JR., Robert E., Lo, Calvin S.
• Granted Patent: US 10,395,676 B2
• Time in Patent Office: Days
• CPC Class Codes: G11B 5/00826 comprising a plurality of single poles or gaps or groups thereof operative at the same time
• CPC Class Codes: G11B 5/00878 transducing different track configurations or formats on the same tape
• CPC Class Codes: G11B 5/3909 Arrangements using a magnetic tunnel junction
• CPC Class Codes: G11B 5/397 with a plurality of independent magnetoresistive active read-out elements for respectively transducing from selected components
• CPC Class Codes: G11B 5/4893 relative to moving tape

Abstract

An apparatus, according to one embodiment, includes a first circuit comprising a pair of terminals coupled to a first read transducer having a tunnel valve structure and a first parallel circuit. A second circuit has a pair of terminals that are coupled to a second read transducer having a tunnel valve structure. An area of a tunnel barrier portion of the second read transducer is larger than an area of a tunnel barrier portion of the first read transducer. The terminal resistance of the first circuit is less than about five times a terminal resistance of the second circuit.

Claims

1. An apparatus, comprising:

a first circuit comprising a pair of terminals coupled to a first read transducer and a first parallel circuit, the first read transducer having a tunnel valve structure having a resistance; and

a second circuit comprising a pair of terminals coupled to a second read transducer having a tunnel valve structure,

wherein an area of a tunnel barrier portion of the second read transducer along a plane of deposition thereof is larger than an area of a tunnel barrier portion of the first read transducer along a plane of deposition thereof,

wherein a terminal resistance of the first circuit is less than about five times a terminal resistance of the second circuit.

2. An apparatus as recited in claim 1, wherein a resistivity of a tunnel barrier of the first read transducer is about the same as a resistivity of a tunnel barrier layer of the second read transducer.

3. An apparatus as recited in claim 1, wherein the first read transducer is a data reader, wherein the second read transducer is a servo reader.

4. An apparatus as recited in claim 1, wherein the area of the tunnel barrier portion of the second read transducer is at least two times the area of the tunnel barrier portion of the first read transducer.

5. An apparatus as recited in claim 1, wherein the first read transducer has a greater height than the second read transducer.

6. An apparatus as recited in claim 1, comprising a plurality of the first read transducers, wherein the first read transducers are arranged in an array, wherein the second read transducer is aligned with a longitudinal axis of the array.

7. An apparatus as recited in claim 1, wherein the first read transducer is a first data reader, wherein the second read transducer is a second data reader.

8. An apparatus as recited in claim 1, wherein the first and second read transducers are in a magnetic tape head.

9. An apparatus as recited in claim 1, wherein the first parallel circuit is coupled to an exterior of a module.

10. An apparatus as recited in claim 1, wherein the first parallel circuit is coupled directly to leads of a cable.

11. An apparatus as recited in claim 10, wherein the first parallel circuit is coupled directly to the leads of the cable toward an end of the cable located closest to the first and second read transducers.

12. An apparatus as recited in claim 1, wherein the first and second circuits are integrated in a module.

13. An apparatus as recited in claim 1, wherein the first parallel circuit is located on a circuit board to which a cable is attached.

14. An apparatus as recited in claim 1, wherein the second circuit comprises a second parallel circuit coupled to the second read transducer, wherein a resistance of the second parallel circuit is different than a resistance of the first parallel circuit.

15. An apparatus as recited in claim 1, further comprising:

a drive mechanism for passing a magnetic medium over the first and second read transducers.

16. An apparatus, comprising:

a module having a first read transducer and a second read transducer, the first and second read transducers each having a tunnel valve structure,

wherein an area of a tunnel barrier portion of the second read transducer along a plane of deposition thereof is larger than an area of a tunnel barrier portion of the first read transducer along a plane of deposition thereof,

a parallel circuit coupled to the first read transducer; and

a second circuit coupled to the second read transducer,

wherein a terminal resistance measured across the parallel circuit and the first read transducer is less than about five times a terminal resistance measured across the second circuit and the second read transducer.

17. An apparatus as recited in claim 16, wherein a resistivity of a tunnel barrier portion of the first read transducer is about the same as a resistivity of a tunnel barrier portion of the second read transducer.

18. An apparatus as recited in claim 16, wherein an area of the tunnel barrier portion of the second read transducer is at least two times an area of the tunnel barrier portion of the first read transducer.

19. An apparatus as recited in claim 16, wherein a resistance of the second circuit is different than a resistance of the parallel circuit.

20. An apparatus as recited in claim 16, wherein the first and second read transducers are in a magnetic tape head.