Magnetic reader with piggybacked fence

#The present invention relates to magnetic head structures, and more particularly, this invention relates to a magnetic head structure having a protective fence paired with a reader.

#Business, science and entertainment applications depend upon computers to process and record data, often with large volumes of the data being stored or transferred to nonvolatile storage media, such as magnetic discs, magnetic tape cartridges, optical disk cartridges, floppy diskettes, or floptical diskettes. Typically, magnetic tape is the most economical and convenient means of storing or archiving the data. Storage technology is continually pushed to increase storage capacity and storage reliability. Improvement in data storage densities in magnetic storage media, for example, has resulted from improved medium materials, improved error correction techniques and decreased areal bit sizes. The data capacity of half-inch magnetic tape, for example, is now measured in hundreds of gigabytes on 512 or more data tracks.

#The improvement in magnetic medium data storage capacity arises in large part from improvements in the magnetic head assembly used for reading and writing data on the magnetic storage medium. A major improvement in transducer technology arrived with the magnetoresistive (MR) sensor originally developed by the IBM® Corporation. The MR sensor transduces magnetic field changes in an MR stripe to resistance changes, which are processed to provide digital signals. Data storage density can be increased because an MR sensor offers signal levels higher than those available from conventional inductive read heads for a given bit area. Moreover, the MR sensor output signal depends only on the instantaneous magnetic field intensity in the storage medium and is independent of the magnetic field time-rate-of-change arising from relative sensor/medium velocity. In operation the magnetic storage medium, such as tape or a magnetic disk surface, is passed over the magnetic read/write (R/W) head assembly for reading data therefrom and writing data thereto.

#For a fuller understanding of the nature and advantages of the present invention, as well as the preferred mode of use, reference should be made to the following detailed description read in conjunction with the accompanying drawings.

#FIG. 1 is a representative tape bearing surface view of a typical multitrack tape head having a multitude of read elements and one or more servo sensors.

#FIG. 2A is a representative tape bearing surface view of a multitrack tape head having a multitude of read elements and one or more servo sensors according to one embodiment of the present invention.

#The following description is the best mode presently contemplated for carrying out the present invention. This description is made for the purpose of illustrating the general principles of the present invention and is not meant to limit the inventive concepts claimed herein. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations.

#It has been observed that MR readers not having piggybacked writers are far more likely to fail due to accumulation of conductive material from the tape at low humidity than read-write transducer pairs. The magnetic head of this invention has a thin-film-deposited and relatively durable piggybacked ‘fence’ adjacent some or all of the sensors. The fence serves as a conductive-debris-accumulating feature, wear-reducing feature, and cooling feature. In brief, the fence is constructed of films that are more durable and less susceptible to recession than the shields surrounding a sensor element, especially a sensor element not having a writer adjacent thereto. This invention is especially suited to servo track read sensors in tape heads, as these conventionally are not fenced as described herein. Servo sensors are critical for positioning the head accurately during writing, and read errors due to resistance fluctuations will quickly cause a tape drive to stop writing. This invention also encompasses other types of magnetic heads, including interleaved heads.

#FIG. 2A illustrates a detailed portion of a magnetic tape head 200 according to one embodiment, as seen when looking at the tape bearing surface. This head is suitable for use with Linear Tape Open (LTO) systems, and is a read-while-write head assembly. As shown, the head includes several R/W pairs 202, each R/W pair including a reader 204 and a writer 206. Heads typically include several R/W pairs, such as 8, 16, 32 pairs, etc. The R/W pairs 202 as shown are linearly aligned. However, the pairs may also be aligned diagonally, staggered, etc.