Abstract: A write head has a variable throat height wherein the throat height is dependent upon the frequency of operation of the write head. At high frequency operation the throat height is small and at low frequency operation the throat height is large. The write head writes hard into a circular track of a rotating magnetic disk at all frequencies but not overly hard at low frequencies thereby avoiding excessive erase bands and adjacent track interference (ATI) on each side of the track being written.

Abstract: A spin valve sensor has a pinned layer structure that has a net positive stress induced uniaxial anisotropy that promotes a pinning of the pinned layer structure in a pinned direction for stabilizing the pinning of the pinned layer structure at high temperatures near to a blocking temperature of a pinning layer which is exchange coupled to the pinned layer.

Abstract: A free layer structure is provided for a spin valve sensor which has a nickel iron based layer and a ferromagnetic oxide layer wherein the cobalt iron oxide layer permits a thin nickel iron layer to be employed while maintaining a desired magnetic softness of the free layer structure and a desirable magnetoresistance of a spin valve sensor.

Abstract: A method of making a multifilm structure is provided for a pinned layer structure of a spin valve sensor for increasing the magnetoresistive coefficient (dr/R) of the sensor and/or decreasing a ferromagnetic coupling field (HF) between the pinned layer structure and the free layer of the sensor. The multifilm structure for the pinned layer in one or both AP layers of an AP pinned layer structure or a single pinned layer structure includes a nickel iron (NiFe) middle layer which is located between a cobalt (Co) first film and a cobalt (Co) second film.

Abstract: A process for resetting or initially establishing the magnetic orientation of one or more spin valves in a magnetoresistive read head with improved robustness. The spin valve includes subcomponents such as an antiferromagnetic layer, a ferromagnetic pinned layer, a conductive layer, a free layer, and a hard bias layer. A first external magnetic field is first applied to the spin valve sensor, this field having a first orientation relative to the spin valve sensor. During application of the first external magnetic field, a pulse of electrical current is directed through the spin valve sensor in a first direction, preferably parallel to the magnetic orientation of the external field. The current waveform brings the antiferromagnetic layer of the spin valve past its blocking temperature, freeing its magnetic orientation. The first external field exerts a robust bias upon the antiferromagnetic layer in the desired direction.

Abstract: A single-sided, notched write head is provided for writing narrow erase band servo tracks as well as a double-notched write head, and for writing data tracks better than a double-notched write head. The single-sided, notched write head writes a narrow erase band on the notched side and a wide erase band on the unnotched side. In one embodiment, only one side of the first pole piece layer is notched, and in another embodiment a first side of the first pole piece layer is notched more than a second side. By writing servo tracks only a fraction of the track width of the write head, a wide erase band region is overwritten so that a narrow erase band is on each side of the servo track. Data tracks are written with a narrow erase band on one side and a wide erase band on the other side. The wide erase band on one side of the data track allows more flexibility in spacing the read head from adjacent tracks.

Abstract: A high magnetization, high resistivity, low corrosion and near zero magnetostriction soft adjacent layer (SAL) is provided for a magnetoresistive (MR) sensor of a read head. The MR sensor may either be an anisotropic MR (AMR) sensor or a spin valve sensor. In both sensors the SAL is CoHfNb or CoHfNbFe. The Hf is added to reduce corrosion and the Hf and Nb are balanced to provide near zero magnetostriction. The addition of Fe is an enhancer for reducing negative magnetostriction without diluting the magnetism of the alloy. Since CoHfNb has significantly higher magnetization than NiFeCr the SAL layer of CoHfNb can be thinner than the SAL of NiFeCr which results in a significantly higher resistance SAL. The higher resistance SAL equates to less shunting of the sense current through the SAL and better signal performance of the MR read head.

Abstract: An improved bow and/or stern seal is provided for a surface effect vehicle herein the vehicle has a pair of spaced apart side hulls which are joined by a wet deck, and the bow and stern seals extend between the side hulls so that an air cushion can be formed between the side walls and the bow and stern seals. The improved seal includes a portion of the deck having an opening for providing an air inlet to the air cushion. An elongated pneumatic bag is mounted along its length to the bottom of the wet deck, is sealed at its ends and is positioned to receive air from the deck opening along its forward side. Provision is made for a passageway between the side hulls for directing air around the forward side of the bag.

Abstract: A vibration isolation module is interposed between a sonar array and its ing cable. A number of nylon cords contained within the vibration isolation module normally bear the load induced by the hydrodynamic drag of the array. Since the nylon cords are encased in a rubber-like envelope, noise and vibrations created by the towing cable are damped and prevented from overly interfering with the responsiveness of the sonar array. When, however, the array's drag is increased by, for example, a faster towing speed, the cords stretch and a central braided member bears the load. The braided member has a strength considerably in excess of the nylon cords to assure that the towed sonar array is not lost. Since the braided member is filled with a viscous material and there are no other voids in the rubber-like envelope, the module can be pulled through a hull penetrator to deploy or retrieve the sonar array.