Abstract: A longitudinal recording head (50, 56, 60) for use with magnetic recording media includes a non-uniform gap (54, 59, 64) between first (51, 57, 61) and second magnetic (52, 58, 62) poles which focuses magnetic flux onto a small area of the magnetic recording medium. The non-uniform gap is preferably in the form of a cavity that is contoured to produce the desired flux pattern. Longitudinal recording heads incorporating the non-uniform gap are capable of improved recording densities.

Abstract: The present invention provides perpendicular recording media having a soft magnetic underlayer and magnetic regions which generate an external magnetic field in the soft magnetic underlayer. The soft magnetic underlayer is brought into a substantially single-domain state by the magnetic field, thereby reducing or eliminating unwanted noise in the soft underlayer. In a preferred embodiment, the recording medium includes a ring-shaped soft magnetic underlayer positioned between concentric ring-shaped magnetic regions.

Abstract: Techniques for ultrahigh density writing on an erasable magnetic medium include using a micromachined mechanism having two probes for writing to the medium. Use of the two probe embodiment eliminates the need to change the magnetic orientation of the probe. In another embodiment, a single probe is provided which is heated to the vicinity of its Curie temperature to enable the magnetic orientation of the probe to be switched. The probe may be heated to its Curie temperature through the use of a heating element or a focused laser. In another embodiment of the present invention, either the magnetic orientation of the probe or the magnetic orientation of the medium may be switched through the combination of a static magnetic field, a radio frequency magnetic field and, under certain circumstances, the magnetic field of the probe. In all cases, the writing techniques enable information to be written to a magnetic medium in a manner which enables the information to be erased and the medium rewritten.

Abstract: An improved thick film sensor for detection of magnetic bubble domains which can be configured to provide soft error detection and full data rate sensing. The sensor can be fabricated using single level masking techniques and is typically a magnetoresistive sensor comprised of NiFe. In its basic configuration, the sensor is comprised of two sets of magnetoresistive elements, each set including a sensor element and a dummy element, where both the sensor element and the dummy element provide a signal due to the bubble domain to be sensed. The magnetoresistive elements are arranged in a bridge circuit to give full data rate sensing and soft error detection. In a preferred embodiment, chevron expander-detectors are used, although the geometry of the sensor and dummy elements is not limited to chevron-type geometries.

Abstract: A nucleator for producing reverse magnetized domains in an amorphous magnetic material capable of supporting such domains. The nucleator is comprised of a current carrying conductor whose current carrying path includes a portion of the amorphous magnetic medium. The amount of current which flows through the conductor and through the amorphous medium is sufficient to nucleate magnetic domains therein. The nucleator can be fabricated as a portion of magnetic elements used to move bubble domains in an amorphous magnetic material and can be implemented using single level metallurgy. Thus, a current conducting nucleator is provided in which current flows through the bubble material itself.