Dynamic magnetic information storage or retrieval – Head – Head surface structure
Reexamination Certificate
2000-07-13
2003-08-05
Evans, Jefferson (Department: 2652)
Dynamic magnetic information storage or retrieval
Head
Head surface structure
C360S236500
Reexamination Certificate
active
06603637
ABSTRACT:
BACKGROUND
The present application relates generally to magnetic recording systems and, in particular, to ion beam treatments for magnetic recording heads and magnetic recording media.
Magnetic alloys are commonly used for forming various parts of magnetic head assemblies used in computer data storage devices. For example, permalloy, a magnetic nickel-iron (NiFe) alloy, has excellent magnetic properties and can be used to form the pole tips on the air bearing surfaces of the head assembly. The air bearing surfaces are the surfaces of the magnetic recording head which contact the magnetic recording medium when the magnetic recording head is not in motion. During operation, the read/write head flies over the recording medium by compressing a fine layer of air to form a low friction gas bearing that maintains the head above, and out of contact with, the recording medium. The spacing between the air bearing surface of the magnetic recording head and the surface of the magnetic recording medium during operation is often referred to as the “fly height.” In general, a small fly height is desirable to minimize distortion of signals sent to and from the magnetic head. A small fly height also can allow a higher density of magnetic transitions in the magnetic recording medium to be recorded.
Despite the good magnetic properties of permalloy and other magnetic alloys, the magnetic tip poles are subject to mechanical wear as the magnetic head is dragged over the magnetic recording medium when rotation of the magnetic recording medium is started or stopped.
Furthermore, with decreased fly heights, there should be no foreign substances on the surface of the pole tips or on the surface of the recording medium. Such foreign substances include coatings which are subject to peeling or flaking.
The magnetic surfaces of head assemblies also are subject to corrosion due to contact with moisture or other chemicals in the air. For example, vaporized water, chlorides and sulfides can corrode permalloy. Other magnetic materials, such as FeAlSi, also are subject to corrosion. Such corrosion, which can occur, for example, after manufacture of the head assembly, but prior to use, can reduce the reliability and accuracy of the head, and can lead to complete failure of the disc drive.
One technique for making the magnetic head more resistant to corrosion is disclosed in U.S. Pat. No. 5,023,738, which is assigned to the assignee of the present application. That patent discloses providing a thin anti-corrosive coating on either the entire magnetic head or portions thereof. Nevertheless, despite the recent improvements in the prevention of corrosion of the head and/or disc, further improvements are desirable to provide comparable resistance to corrosion using even thinner films. Similarly, further improvements in the tribology of the magnetic head-magnetic medium interface are desirable to enable further reductions in the fly height.
SUMMARY OF THE INVENTION
In general, techniques are disclosed for improving the tribology between an air bearing surface of a magnetic recording head and a magnetic recording medium. In addition, techniques are described for reducing resistance to wear and corrosion of the air bearing surface of the recording head as well as resistance to corrosion of the recording medium. Various ion beam techniques can be used to enhance the properties of the recording head and recording medium, and include ion implant techniques, ion mixing techniques and ion burnishing techniques.
According to one aspect, a method of fabricating a magnetic recording head includes implanting ions below an air bearing surface of the recording head.
According to another aspect, a method of fabricating a magnetic recording head includes forming a coating over a surface of the recording head, wherein the surface includes pole tips. Atoms from the coating are subsequently implanted into regions of the recording head below the coating using an ion beam mixing technique.
In yet another aspect, a method of fabricating a magnetic recording head includes providing a lubricating film over a surface of the recording head, wherein the surface includes pole tips and burnishing the film using an ion beam burnishing technique.
Using those or other techniques, a magnetic recording head can include a slider having an air bearing surface and a transducer with magnetic poles including pole tips substantially flush with the air bearing surface. The recording head has ions implanted below the air bearing surface. Similarly, a magnetic recording head can include a slider and a transducer mounted on the slider. The transducer can include magnetic poles having pole tips. A coating is provided over the pole tips to form an air bearing surface of the head. Atoms from the coating are implanted in one or more layers under the coating.
According to another aspect, a method of fabricating a magnetic recording medium includes implanting ions into a magnetic film of the recording medium.
In yet a further aspect, a method of fabricating a magnetic recording medium includes forming a coating above a magnetic film on the recording medium. Ions from the coating then are implanted into the magnetic film using an ion beam mixing technique.
According to another aspect, a method of fabricating a magnetic recording medium includes providing a lubricating film over a magnetic film in the recording medium. The lubricating film is subsequently burnished using an ion beam burnishing technique.
Using those or other techniques, a magnetic recording medium can include a substrate and a magnetic film disposed over the substrate with ions implanted into the magnetic film. Similarly, a magnetic recording medium can include a substrate, a magnetic film disposed over the substrate, and a coating disposed over the magnetic film. Atoms from the coating are implanted in the magnetic film.
Various implementations of the foregoing techniques and the magnetic recording heads and media include one or more of the following features. Ions can be implanted into pole tips of the recording head, over substantially the entire surface of the transducer, or over substantially the entire surface of the air bearing surface.
Different types of ions can be implanted, including metallic or reactive ions, as well as a mixture of ions that forms a solid lubricant. The energy of the ions in the various techniques will depend on the particular implementation. However, in some cases, energies in the range of about 2 keV to about 500 keV can be used.
When a coating is provided over the magnetic film of the recording medium or on the recording head to serve as an air bearing surface, the coating can include materials such as a metallic material or a solid lubricant, and can be relatively thin. Thus, in some implementations, the coating may have a thickness in the range of about 20 to about 100 angstroms. Atoms from the coating can then be implanted into the underlying layers using ion beam mixing.
For embodiments in which a lubricating film is provided, the lubricating film can be applied topically and bombarded with gaseous ions. The lubricating film can be applied, for example, by a dipping, painting, spraying or similar process prior to burnishing the lubricating film with ion beams.
One or more of the following advantages are present in some implementations. The various ion beam techniques can be used to improve the tribology of the interface between a recording head and a recording medium. For example, the ion beam techniques can help reduce stiction and mechanical wear of the air bearing surfaces of the recording head and/or the upper surface of the recording medium. Thus, reduced fly heights can be obtained, thereby allowing greater densities of magnetic transitions to be recorded in the magnetic recording medium. The ion beam techniques also can provide comparable resistance to corrosion of those surfaces using relatively thin protective films and, in some cases, even in the absence of a protective film. In some cases, the ion beam techniques can provide greater resistance to corro
Berkowitz Jeffery K.
Gupta Bal K.
Sahu Sanghamitra
Segar Peter R.
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