Hard disk drive with contact detection using a spin torque oscillator

• US 9,355,668 B2
• Filed: 05/21/2013
• Issued: 05/31/2016
• Est. Priority Date: 05/21/2013
• Status: Active Grant

• Current Assignee: JP Morgan Chase Bank, N.A. (JP Morgan Chase & Co)
• Original Assignee: HGST Netherlands B.V. (Western Digital Corporation)
• Inventors: Nishida, Yasutaka, Shiimoto, Masato, Katada, Hiroyuki, Tagawa, Ikuya, Xu, Junguo
• Primary Examiner(s): POLO, GUSTAVO D
• Application Number:
  US13/899,334
• Publication Number:
  US 20140347969A1
• Time in Patent Office: 1,106 Days
• Field of Search: 360/31, 360/75, 360/125.3, 360/125.31, 360/125.32, 360/125.71, 360/125.74, 360/125.75, 360/128, 360/234.4
• US Class Current: 1/1
• CPC Class Codes: G11B 2005/0024 Microwave assisted recording
• CPC Class Codes: G11B 5/6076 Detecting head-disk contact

Abstract

A hard-disk drive having a structurally efficient magnetic head slider utilizes a MAMR-based spin torque oscillator (STO) for head-disk contact detection and for flying height sensing. Contact detection and spacing estimation techniques consider the nominal temperature difference, and thus different criteria, between read and write operations.

Claims

1. A hard-disk drive, comprising:

a head slider comprising a read/write head comprising a spin torque oscillator (STO) element;

a magnetic-recording disk rotatably mounted on a spindle;

a voice coil motor configured to move the head slider to access portions of the magnetic-recording disk; and

at least one an electronic component configured to;

monitor the resistance of said STO element, and

detect a contact event between said head slider and said magnetic-recording disk based on said resistance of said STO element and based on different respective criteria depending on whether a read operation is being performed or a write operation is being performed.

2. The hard-disk drive of claim 1, wherein said electronic component is a first electronic component and is further configured to output a resistance value of said STO element, said hard-disk drive further comprising:

a second electronic component configured to;

receive said resistance value output from said first electronic component, and

estimate a non-zero spacing between said head slider and said magnetic-recording disk based on said resistance value.

3. The hard-disk drive of claim 2, wherein said second electronic component is further configured to estimate the non-zero spacing between said head slider and said magnetic-recording disk based on different criteria depending on whether a read operation is being performed or a write operation is being performed.

4. The hard-disk drive of claim 2,

wherein said head slider further comprises an embedded contact sensor (ECS) element;

wherein said first electronic component is further configured to monitor and output the resistance of said ECS element; and

wherein said second electronic component is further configured to estimate the spacing between said head slider and said magnetic-recording disk based on said resistance of said STO element and said resistance of said ECS element.

5. The hard-disk drive of claim 1,

wherein said electronic component is further configured to apply a first current to said STO element for detecting a contact event during a read operation and to apply a different second current to said STO element for detecting a contact event during a write operation.

6. The hard-disk drive of claim 1, wherein said STO element is positioned between a main write pole and a magnetic shield of said read/write head.

13. The hard disk drive of claim 1, wherein said different respective criteria are based on corresponding STO element nominal temperatures associated with a read operation and with a write operation, respectively.

7. An electronic component configured for use in a hard-disk drive, said electronic component comprising a memory and a processor, the memory embodying one or more sequences of instructions which, when executed by the processor, cause performance of:

monitoring the resistance of a spin torque oscillator (STO) element positioned in a read/write head of said hard-disk drive; and

detecting a contact event between a head slider and a magnetic-recording disk based on said resistance of said STO element and based on different respective criteria depending on whether a read operation is being performed or a write operation is being performed.

8. The electronic component of claim 7, wherein said one or more sequences of instructions which, when executed, cause performance of applying a first current to said STO element for detecting a contact event during a read operation and applying a different second current to said STO element for detecting a contact event during a write operation.

9. An electronic component configured for use in a hard-disk drive, said electronic component comprising a memory and a processor, the memory embodying one or more sequence of instructions which, when executed by the processor, cause performance of:

receiving a resistance value output from an electronic component configured to monitor the resistance of a spin torque oscillator (STO) element positioned in a read/write head of said hard-disk drive, and

estimating a non-zero spacing between a head slider and a magnetic-recording disk of said hard-disk drive based on said resistance value and based on different criteria depending on whether a read operation is being performed or a write operation is being performed.

10. A method for flying height sensing in a hard-disk drive comprising a head slider having an embedded spin torque oscillator (STO), the method comprising:

monitoring the resistance of said STO element; and

detecting a contact event between said head slider and a magnetic-recording disk of said hard-disk drive based on said resistance of said STO element and based on different criteria depending on whether a read operation is being performed or a write operation is being performed.

11. The method of claim 10, further comprising:

estimating a non-zero spacing between said head slider and a magnetic-recording disk based on said resistance of said STO.

12. The method of claim 11, wherein said estimating further comprises estimating the non-zero spacing between said head slider and said magnetic-recording disk based on different criteria depending on whether a read operation is being performed or a write operation is being performed.

14. The method of claim 11, wherein said estimating further comprises estimating the non-zero spacing based on spacing-based temperature changes in said STO element.