1. A magnetic head comprising:
a pinned layer;
a free layer; and
a current screen layer for confining current therein and having a first part with a thickness greater than a thickness of a second part, a direction of the thicknesses of the first and second parts in a direction normal to a film plane, the current screen layer configured to pass a sense current substantially perpendicular to the film plane.
2. The magnetic head according to claim 1, wherein the current screen layer comprises:
high resistance areas comprising an oxide, a nitride, a fluoride, or a carbide; and
low resistance areas configured to exhibit an electrical resistance that is lower relative to the high resistance areas.
3. The magnetic head according to claim 1, wherein the second part is configured to exhibit an electrical resistance that is lower relative to the first part.
4. The magnetic head according to claim 1, wherein the current screen layer is formed between the pinned layer and the free layer.
5. The magnetic head according to claim 4, wherein a non-magnetic intermediate layer is provided between the pinned layer and the current screen layer.
6. The magnetic head according to claim 4, wherein a non-magnetic intermediate layer is provided between the current screen layer and the free layer.
7. The magnetic head according to claim 1, wherein tthick\u2212tthin>0.2 nm provided that a film thickness of the thickest part of the current screen layer is defined as tthick, and a film thickness of the thinnest part thereof is defined as tthin.
8. The magnetic head according to claim 1, further comprising a write head provided with magnetic poles and coils.
9. A magnetoresistive head and magnetic storage apparatus comprising:
a magnetic disk;
a drive means for rotating said magnetic disk;
a magnetic head for executing recording operation and reading operation against said magnetic disk; and
a head driver for executing positioning of said magnetic head over said magnetic disk,
wherein said magnetic head includes:
a pinned layer;
a free layer; and
a current screen layer for confining current therein and having a first part exhibiting a thickness greater than a thickness of a second part, a direction of the thickness of the first and second parts in a direction normal to a film plane, and
wherein the current screen layer is configured to pass a sense current in a direction substantially perpendicular to the film plane.
10. A method for manufacturing a magnetic head comprising the steps of:
forming a pinned layer with a magnetization direction thereof, effectively pinned in one direction, over a substrate;
forming a current screen layer;
flattening the surface of said current screen layer; and
forming a free layer with a magnetization direction thereof, undergoing a change according to an external field.
11. The method for manufacturing a magnetic head, according to claim 10, wherein the step of flattening the surface of said current screen layer is executed through etching by reverse sputtering, ion beam etching, or gas cluster ion beam etching.
12. The method for manufacturing a magnetic head, according to claim 10, further comprising the step of forming a non-magnetic intermediate layer before, andor after the formation of said current screen layer.
13. The method for manufacturing a magnetic head, according to claim 10, wherein the current screen layer is formed of high resistance areas each comprising an oxide, a nitride, a fluoride, or a carbide, and low resistance areas relatively low in resistance in comparison with the high resistance areas.
14. The method for manufacturing a magnetic head, according to claim 10, wherein parts of the current screen layer, relatively small in film thickness, become low resistance areas where current is liable to flow with ease.
15. The method for manufacturing a magnetic head, according to claim 10, wherein the current screen layer is formed between the pinned layer and the free layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An EGR device comprising:
a first cooling passage configured to introduce a flowing medium discharged from an engine into a main radiator so that the flowing medium is cooled therein and then the flowing medium returns to the engine;
a second cooling passage configured to introduce a part of the flowing medium cooled in the first cooling passage to a sub-radiator so that the flowing medium is further cooled therein, the second cooling passage configured to introduce the flowing medium to an EGR cooler to return the flowing medium, which is discharged from the EGR cooler, to the engine; and
a flow regulating means capable of regulating a flow amount of the flowing medium that is cooled in the first cooling passage so as to be introduced into the sub-radiator,
wherein the main radiator and the sub-radiator are combined to form a radiator having a tank as one unit,
wherein an inner space of the tank of the radiator is separately divided by a partition plate that is provided with a communicating hole therein to form the tank of the main radiator and the tank of the sub-radiator, and
wherein the flow regulating means has a piston type orifice valve including a piston having an orifice for obtaining a certain opening area relative to an area of the communicating hole of the partition plate, the piston being able to open and close the orifice, and a driving means that drives the piston.
2. The EGR valve according to claim 1, wherein the flow regulating means is for controlling an increase in a ratio of a first cooling passage side flow amount to a second cooling passage side flow amount as an engine load becomes larger.
3. The EGR valve according to claim 1, further comprising:
a water cooled intercooler associated with the second cooling passage,
wherein a part of the flowing medium that is cooled in the first cooling passage is introduced into the sub-radiator so as to be further cooled, then introduced to the water cooled intercooler and the EGR cooler in order thereof.
4. The EGR valve according to claim 3, wherein the flow regulating means is for controlling an increase in a ratio of a first cooling passage side flow amount to a second cooling passage side flow amount as an engine load becomes larger.