Integrated servo and read EMR sensor
View Patent ↗An integrated servo and read device implementing Extraordinary Magnetoresistive (EMR) sensors. In one embodiment, dedicated EMR sensors are employed: one for data reading and one for servo operations. The sensors are preferably configured in an abutted configuration. In addition to magnetic recording systems, the device is also useful in a magnetic imaging device such as a scanning magnetometer. The integrated device may also be useful in other devices requiring a high sensitivity, high resolution sensor.
1. A sensor, comprising:
a first Extraordinary Magnetoresistive (EMR) device for detecting magnetic fields of a magnetic domain of interest;
a second EMR device for deriving servoing information for positioning the first EMR device over the magnetic domain of interest,
wherein each EMR device comprises:
a layer of electrically conductive material;
a layer of semi-conductor material formed adjacent to and contacting the layer of electrically conductive material, the layer of semi-conductor material having an edge surface opposite the electrically conductive material and having first and second ends separated by a length (L);
first and second electrically conductive current leads, in electrical communication with the semi-conductor material; and
first and second electrically conductive voltage leads in electrical communication with the semi-conductor material, the second current lead being located between the first and second voltage leads.
2. A sensor as recited in claim 1 , wherein the EMR devices are electrically isolated by an electrically nonconductive spacer or a void.
3. A sensor as recited in claim 1 , wherein the devices are designed for generally collinear and tangential alignment with a single magnetic domain track for deriving servoing information from the magnetic domain track.
4. A sensor as recited in claim 3 , wherein the voltage leads on the second EMR device are laterally translated with respect to a center axis of the first EMR device.
5. A sensor as recited in claim 3 , wherein the voltage leads on the second EMR device are spaced farther apart than the voltage leads of the first EMR device.
6. A sensor as recited in claim 1 , wherein the second EMR device derives servoing information from a magnetic domain track other than the magnetic domain being detected by the first EMR device.
7. A sensor as recited in claim 6 , wherein the voltage leads of the second EMR device are displaced, with respect to the voltage leads of the first EMR device, by at least a width of one full magnetic domain track and/or one or more guard bands.
8. A sensor as recited in claim 7 , wherein the voltage leads of the second EMR device enable the second EMR device to derive servoing information from a N+x magnetic domain track, where N is the magnetic domain track being detected by the first EMR device, and where x is greater than 1.
9. A sensor as recited in claim 6 , wherein at least one of a length (L) and width (W) of the second EMR device is different than an L or W of the first EMR device.
10. A sensor as recited in claim 1 , wherein the first EMR device reads data from a magnetic medium, the magnetic domain being a data track on the magnetic medium.
11. A sensor as recited in claim 1 , further comprising at least a third EMR device for detecting magnetic fields of at least a second magnetic domain of interest.
12. A sensor as recited in claim 11 , further comprising at least one EMR device other than the second EMR device for also deriving servoing information.
13. A sensor as recited in claim 11 , further comprising a plurality of write elements for selectively writing the magnetic domains of interest.
14. A sensor as recited in claim 1 , wherein the sensor detects a position of grains comprising a recording medium.
15. A sensor as recited in claim 1 , wherein the sensor is used for magnetometry.
16. A sensor as recited in claim 1 , wherein the sensor is used for magnetic imaging.
17. A sensor as recited in claim 1 , wherein the first and second voltage leads are each separated by a distance of about the size of a magnetic region or bit to be resolved or imaged.
18. A magnetic storage system, comprising:
magnetic media containing magnetic domain tracks of interest;
at least one head for reading from and writing to the magnetic media, each head having:
a sensor according to claim 1 ;
a writer coupled to the sensor;
a slider for supporting the head; and
a control unit coupled to the head for controlling operation of the head.
19. A system as recited in claim 18 , wherein the EMR devices are designed for generally collinear and generally tangential alignment with a single magnetic domain track on the media for reading data from and deriving servo control from the same magnetic domain track.
20. A system as recited in claim 18 , wherein the magnetic media includes servo information, the second EMR device reading the servo information, wherein the servo information includes only synchronization and cylinder labeling information.
21. A system as recited in claim 20 , wherein the servo information is found in the magnetic domain track being read by the first EMR device.
22. A system as recited in claim 20 , wherein the servo information is found in a magnetic domain track other than the magnetic domain track being read by the first EMR device.
23. A scanning magnetometer, comprising:
a chuck for holding a workpiece;
an actuator; and
a sensor as recited in claim 1 coupled to the actuator for movement over the chuck.
24. A scanning magnetic imaging device, comprising:
a chuck for holding a workpiece;
an actuator; and
a sensor as recited in claim 1 coupled to the actuator for movement over the chuck.