Resistive temperature sensors for improved asperity, head-media spacing, and/or head-media contact detection

Patent metadata

Field	Value
Publication number	US-2016372144-A1
Application number	US-201615251663-A
Country	US
Kind code	A1
Filing date	Aug 30, 2016
Priority date	Nov 17, 2010
Publication date	Dec 22, 2016
Grant date	—

Abstract

A sensor supported by a head transducer has a temperature coefficient of resistance (TCR) and a sensor resistance. The sensor operates at a temperature above ambient and is responsive to changes in sensor-medium spacing. Conductive contacts connected to the sensor have a contact resistance and a cross-sectional area adjacent to the sensor larger than that of the sensor, such that the contact resistance is small relative to the sensor resistance and negligibly contributes to a signal generated by the sensor. A multiplicity of head transducers each support a TCR sensor and a power source can supply bias power to each sensor of each head to maintain each sensor at a fixed temperature above an ambient temperature in the presence of heat transfer changes impacting the sensors. A TCR sensor of a head transducer can include a track-oriented TCR sensor wire for sensing one or both of asperities of the medium.

First claim

1 - 25 . (canceled)

26 . An apparatus, comprising:
a head transducer configured to interact with a magnetic recording medium having a plurality of tracks; and a sensor having a temperature coefficient of resistance and arranged at the head transducer so that a longitudinal axis of the sensor is oriented substantially parallel relative to the tracks, the sensor configured to sense for asperities of the medium.

27 . The apparatus of claim 26 , wherein the sensor is configured to sense for changes in spacing between the head transducer and the medium.

28 . The apparatus of claim 26 , wherein the sensor is configured to sense for changes in spacing and contact between the head transducer and the medium.

29 . The apparatus of claim 26 , wherein the sensor is operated at a temperature above an ambient temperature.

30 . The apparatus of claim 26 , wherein the sensor comprises a wire having the temperature coefficient of resistance.

31 . The apparatus of claim 26 , wherein the sensor comprises a wire having the temperature coefficient of resistance coupled at opposing ends to a first electrical contact and a second electrical contact, the first and second electrical contacts oriented approximately orthogonal to the wire and axially offset from one another.

32 . The apparatus of claim 26 , wherein the sensor comprises a wire having the temperature coefficient of resistance coupled at opposing ends to a first electrical contact and a second electrical contact, the first and second electrical contacts oriented approximately orthogonal to the tracks of the medium.

33 . The apparatus of claim 26 , wherein the sensor is capable of sensing an asperity having a size of less than about 500 nm.

34 . The apparatus of claim 26 , wherein the sensor is capable of sensing an asperity having a size of less than about 200 nm.

35 . The apparatus of claim 26 , wherein the sensor is capable of sensing an asperity having a size of about 35 nm.

36 . The apparatus of claim 26 , wherein the sensor comprises a wire having an effective cross-track width, w eff , defined by w eff =w+l sin α, where w is a physical width of the wire, l is a length of the wire, and α is a skew angle of the head transducer relative to the tracks.

37 . The apparatus of claim 26 , wherein the sensor is situated at or near a close point of the head transducer.

38 . A method, comprising:
moving a magnetic recording medium having tracks relative to a head transducer; and sensing for asperities of the medium using a sensor of the head transducer, the sensor having a temperature coefficient of resistance and a longitudinal axis oriented substantially parallel relative to tracks of the medium.

39 . The method of claim 38 , wherein sensing comprises sensing for changes in spacing between the sensor and the medium.

40 . The method of claim 38 , wherein sensing comprises sensing for changes in spacing and contact between the sensor and the medium.

41 . The method of claim 38 , wherein the sensor comprises a wire having the temperature coefficient of resistance coupled at opposing ends to a first electrical contact and a second electrical contact, the first and second electrical contacts oriented approximately orthogonal to the wire and axially offset from one another.

42 . The method of claim 38 , wherein the sensor is capable of sensing an asperity having a size of less than about 200 nm.

43 . The method of claim 38 , wherein the sensor is capable of sensing an asperity having a size of about 35 nm.

44 . The method of claim 38 , wherein the sensor comprises a wire having an effective cross-track width, w eff , defined by w eff =w+l sin α, where w is a physical width of the wire, l is a length of the wire, and α is a skew angle of the head transducer relative to the tracks.

45 . The method of claim 38 , wherein sensing comprises sensing at or near a close point of the head transducer.

Assignees

• Seagate Technology Llc

Inventors

• Anaya-Dufresne Manuel Charles
• Karr Brian William
• Kunkel Gary Joseph
• Wei Zhen

Classifications

• G11B5/607 Primary

  using thermal means · CPC title

• G11B5/6076

  Detecting head-disk contact · CPC title

• G11B5/40

  Protective measures on heads, e.g. against excessive temperature  (G11B5/31 takes precedence; protection against wear G11B5/255  {; protective structure of the head: see under structures, e.g. G11B5/3106}) · CPC title

• G11B5/255 Primary

  comprising means for protection against wear {(in thin film structures G11B5/3106)} · CPC title

• G11B7/0948

  specially adapted for detection and avoidance or compensation of imperfections on the carrier, e.g. dust, scratches, dropouts (G11B7/095 takes precedence) · CPC title