Magnetic domain control for an embedded contact sensor for a magnetic recording head
View Patent ↗A head for magnetic data recording that includes an embedded contact sensor. The embedded contact sensor detects head disk contact by detecting changes in temperature as a result of contact between the head and the disk. The embedded contact sensor includes a thermoresistive layer and a structure for pinning the magnetic domains of the thermoresistive layer. This pinning of the magnetic domains prevents the thermoresistive layer from changing resistance in response to magnetic fields (rather than temperature) so as to avoid unwanted signal noise as a result of a magnetic signal from the magnetic media.
1. A slider for use in a magnetic data recording system, the slider comprising:
a slider body;
a magnetic head formed on a trailing edge of the slider body, the magnetic head including a magnetic read element, a magnetic write element and an embedded contact sensor, the embedded contact sensor including a thermoresistive layer; and a structure for pinning magnetic domains in the thermoresistive layer.
2. The slider as in claim 1 wherein the structure for pinning the magnetic domains in the thermoresistive layer comprises a hard magnetic layer formed at a side of the thermoresistive layer, the hard magnetic layer producing a magnetic field that pins magnetic domains in the thermoresistive layer.
3. The slider as in claim 2 wherein the hard magnetic layer comprises CoPt or CoPtCr.
4. The slider as in claim 1 wherein the structure for pinning magnetic domains in the thermoresistive layer comprises a layer of antiferromagnetic material that is exchange coupled with the thermoresistive layer.
5. The slider as in claim 4 wherein the layer of antiferromagnetic material comprises IrM or PtMn.
6. The slider as in claim 1 further comprising circuitry connected with the thermoresistive layer for detecting a change in resistance of the thermoresisive layer as a result of a change in temperature.
7. The slider as in claim 1 wherein the thermoresistive layer comprises a single layer of material having a resistance that changes in response to temperature.
8. The slider as in claim 1 wherein the thermoresistive layer consists of Ni, Fe, Co or a combination of these materials.
9. A magnetic data recording system, comprising:
a housing;
a magnetic media rotatably mounted within the housing;
an actuator;
a slider connected with the actuator for movement adjacent to the magnetic medium, the slider further comprising:
a slider body;
a magnetic head formed on a trailing edge of the slider body, the magnetic head including a magnetic read element, a magnetic write element and an embedded contact sensor, the embedded contact sensor including a thermoresistive layer; and a structure for pinning magnetic domains in the thermoresistive layer.
10. The magnetic data recording system as in claim 9 wherein the structure for pinning the magnetic domains in the thermoresistive layer comprises a hard magnetic layer formed at a side of the thermoresistive layer, the hard magnetic layer producing a magnetic field that pins magnetic domains in the thermoresistive layer.
11. The magnetic data recording system as in claim 9 wherein the structure for pinning magnetic domains in the thermoresistive layer comprises a layer of anti ferromagnetic material that is exchange coupled with the thermoresistive layer.
12. The magnetic data recording system as in claim 9 further comprising circuitry connected with the thermoresistive layer for detecting a change in resistance of the thermoresisive layer as a result of a change in temperature.