Recording by magnetisation or demagnetisation of a record carrier Reproducing by magnetic means Record carriers therefor

GPHYSICS G11Information storage G11BINFORMATION STORAGE BASED ON RELATIVE MOVEMENT BETWEEN RECORD CARRIER AND TRANSDUCER

G11B5/00Recording by magnetisation or demagnetisation of a record carrier Reproducing by magnetic means Record carriers therefor

G11B5/004Recording on, or reproducing or erasing from, magnetic drums G11B5/008Recording on, or reproducing or erasing from, magnetic tapes, sheets G11B5/00804magnetic sheets G11B5/00808magnetic cards G11B5/00813magnetic tapes G11B5/00817on longitudinal tracks only G11B5/00821using stationary heads G11B5/00826comprising a plurality of single poles or gaps or groups thereof operative at the same time G11B5/0083for parallel information processing G11B5/00834using virtual scanning heads G11B5/00839using cyclically driven heads providing segmented tracks G11B5/00847on transverse tracks G11B5/00852using stationary heads G11B5/00856comprising a plurality of single poles or gaps or groups thereof operative in time sequence G11B5/0086using cyclically driven heads providing segmented tracks G11B5/00865for transducing on more than one segment simultaneously G11B5/00869the segments being disposed in different lateral zones of the tape G11B5/00873the segments being disposed in different longitudinal zones of the tape G11B5/00878transducing different track configurations or formats on the same tape G11B5/00882configurations only G11B5/00886simultaneously G11B5/00891formats only G11B5/00895simultaneously G11B5/012Recording on, or reproducing or erasing from, magnetic discs G11B5/016using magnetic foils G11B5/02Recording, reproducing, or erasing methods Read, write or erase circuits therefor G11B5/022H-Bridge head driver circuit, the "H" configuration allowing to inverse the current direction in the head G11B5/024Erasing G11B5/0245Bulk erasing G11B5/027Analogue recording G11B5/0275Boundary displacement recording G11B5/03Biasing G11B5/035Equalising G11B5/09Digital recording G11B5/10Structure or manufacture of housings or shields for heads G11B5/102Manufacture of housing G11B5/105Mounting of head within housing or assembling of head and housing G11B5/11Shielding of head against electric or magnetic fields G11B5/112Manufacture of shielding device G11B5/115Shielding devices arranged between heads or windings G11B5/127Structure or manufacture of heads G11B5/1272Assembling or shaping of elements G11B5/1274with "composite" cores G11B5/1276including at least one magnetic thin film G11B5/1278specially adapted for magnetisations perpendicular to the surface of the record carrier G11B5/133with cores composed of particles G11B5/1335Assembling or shaping of elements G11B5/147with cores being composed of metal sheets, i.e. laminated cores with cores composed of isolated magnetic layers G11B5/1475Assembling or shaping of elements G11B5/153with tape-wound cores G11B5/17Construction or disposition of windings G11B5/187Structure or manufacture of the surface of the head in physical contact with, or immediately adjacent to the recording medium Pole pieces Gap features G11B5/1871Shaping or contouring of the transducing or guiding surface G11B5/1872for improving the form of the electrical signal transduced G11B5/1874specially adapted for composite pole pieces G11B5/1875"Composite" pole pieces G11B5/1877including at least one magnetic thin film G11B5/1878disposed immediately adjacent to the transducing gap G11B5/193the pole pieces being ferrite or other magnetic particles G11B5/21the pole pieces being of ferrous sheet metal or other magnetic layers G11B5/23Gap features G11B5/232Manufacture of gap G11B5/235Selection of material for gap filler G11B5/245comprising means for controlling the reluctance of the magnetic circuit in a head with single gap, for co-operation with one track G11B5/2452where the dimensions of the effective gap are controlled G11B5/2455the magnetic circuit including at least one magnetic thin film of controllable properties G11B5/2457disposed immediately adjacent to the gap G11B5/255comprising means for protection against wear G11B5/265Structure or manufacture of a head with more than one gap for erasing, recording or reproducing on the same track G11B5/2651Manufacture G11B5/2652with more than one gap simultaneously operative G11B5/2654for recording or erasing G11B5/2655with all the gaps disposed within the track or "guard band" between tracks G11B5/2657all the gaps having the same dimension in the direction transverse to the track direction G11B5/2658for recording with premagnetization or biasing of record carrier or head G11B5/29Structure or manufacture of unitary devices formed of plural heads for more than one track G11B5/295Manufacture G11B5/31using thin films G11B5/3103Structure or manufacture of integrated heads or heads mechanically assembled and electrically connected to a support or housing G11B5/3106where the integrated or assembled structure comprises means for conditioning against physical detrimental influence G11B5/3109Details G11B5/3113for improving the magnetic domain structure or avoiding the formation or displacement of undesirable magnetic domains G11B5/3116Shaping of layers, poles or gaps for improving the form of the electrical signal transduced G11B5/312for reducing flux leakage between the electrical coil layers and the magnetic cores or poles or between the magnetic cores or poles G11B5/3123by using special coil configurations or conductors G11B5/3126using superconductors G11B5/313Disposition of layers G11B5/3133including layers not usually being a part of the electromagnetic transducer structure and providing additional features G11B5/3136for reducing the pole-tip-protrusion at the head transducing surface G11B5/314where the layers are extra layers normally not provided in the transducing structure G11B5/3143including additional layers for improving the electromagnetic transducing properties of the basic structure G11B5/3146magnetic layers G11B5/315Shield layers on both sides of the main pole G11B5/3153including at least one magnetic thin film coupled by interfacing to the basic magnetic thin film structure G11B5/3156providing interaction by induced or exchange coupling G11B5/3159supraconductive layers G11B5/3163Fabrication methods or processes specially adapted for a particular head structure G11B5/3166Testing or indicating in relation thereto G11B5/3169Working or finishing the interfacing surface of heads G11B5/3173Batch fabrication G11B5/3176Structure of heads comprising at least in the transducing gap regions two magnetic thin films disposed respectively at both sides of the gaps G11B5/3179the films being mainly disposed in parallel planes G11B5/3183intersecting the gap plane G11B5/3186parallel to the gap plane G11B5/3189Testing G11B5/3193of films or layers G11B5/3196of thin magnetic films G11B5/325Erasing heads using permanent magnets G11B5/33Structure or manufacture of flux-sensitive heads G11B5/332using thin films G11B5/335with saturated jig G11B5/35having vibrating elements G11B5/37using galvano-magnetic devices G11B5/372in magnetic thin films G11B5/374Integrated structures G11B5/376in semi-conductors G11B5/378Integrated structures G11B5/39using magneto-resistive devices or effects G11B5/3903using magnetic thin film layers or their effects, the films being part of integrated structures G11B5/3906Details related to the use of magnetic thin film layers or to their effects G11B5/3909Arrangements using a magnetic tunnel junction G11B5/3912Arrangements in which the active read-out elements are transducing in association with active magnetic shields G11B5/3916Arrangements in which the active read-out elements are coupled to the magnetic flux of the track by at least one magnetic thin film flux guide G11B5/3919the guide being interposed in the flux path G11B5/3922the read-out elements being disposed in magnetic shunt relative to at least two parts of the flux guide structure G11B5/3925the two parts being thin films G11B5/3929Disposition of magnetic thin films not used for directly coupling magnetic flux from the track to the MR film or for shielding G11B5/3932Magnetic biasing films G11B5/3935Flux closure films not being part of the track flux guides G11B5/3938the flux closure films being used for absorbing or reducing demagnetisating or saturating fields G11B5/3941the flux closure films being used for providing a closed magnetic circuit to the MR film G11B5/3945Heads comprising more than one sensitive element G11B5/3948the sensitive elements being active read-out elements G11B5/3951the active elements being arranged on several parallel planes G11B5/3954the active elements transducing on a single track G11B5/3958the active elements being arranged in a single plane G11B5/3961disposed at an angle to the direction of the track or relative movement G11B5/3964for transducing on a single track G11B5/3967Composite structural arrangements of transducers G11B5/397with a plurality of independent magnetoresistive active read-out elements for respectively transducing from selected components G11B5/3974from the same information track G11B5/3977from different information tracks G11B5/398Specially shaped layers G11B5/3983with current confined paths in the spacer layer G11B5/3987with provision for closing the magnetic flux during operation G11B5/399with intrinsic biasing G11B5/3993in semi-conductors G11B5/40Protective measures on heads G11B5/41Cleaning of heads G11B5/455Arrangements for functional testing of heads Measuring arrangements for heads G11B5/4555by using a spin-stand G11B5/465Arrangements for demagnetisation of heads G11B5/48Disposition or mounting of heads or head supports relative to record carriers ; arrangements of heads G11B5/4806specially adapted for disk drive assemblies G11B5/4813Mounting or aligning of arm assemblies G11B5/4826Mounting, aligning or attachment of the transducer head relative to the arm assembly G11B5/483Piezo-electric devices between head and arm G11B5/4833Structure of the arm assembly G11B5/484Integrated arm assemblies G11B5/4846Constructional details of the electrical connection between arm and support G11B5/4853Constructional details of the electrical connection between head and arm G11B5/486with provision for mounting or arranging electrical conducting means or circuits on or along the arm assembly G11B5/4866the arm comprising an optical waveguide G11B5/4873the arm comprising piezoelectric or other actuators for adjustment of the arm G11B5/488Disposition of heads G11B5/4886relative to rotating disc G11B5/4893relative to moving tape G11B5/49Fixed mounting or arrangements G11B5/4907Details for scanning G11B5/4915Structure of specially adapted heads G11B5/4923in which zones of the transducing part are being physically controllable G11B5/493Control of magnetic properties G11B5/4938of thin magnetic films G11B5/4946for formation or displacement of magnetic domains G11B5/4953part of the structure being mechanically or magnetically coupled to or decoupled from, the transducing part G11B5/4961Circuits G11B5/4969Details for track selection or addressing G11B5/4976Disposition of heads G11B5/4984Structure of specially adapted switching heads G11B5/4992Circuits G11B5/50Interchangeable mountings G11B5/52with simultaneous movement of head and record carrier G11B5/53Disposition or mounting of heads on rotating support G11B5/531Disposition of more than one recording or reproducing head on support rotating cyclically around an axis G11B5/532Parallel to the direction of movement of the tape G11B5/534inclined relative to the direction of movement of the tape G11B5/535perpendicular to the direction of movement of the tape G11B5/537with all the heads disposed in a plane substantially parallel to the plane of the tape G11B5/538Disposition or mounting of pole pieces on rotating support G11B5/54with provision for moving the head into or out of its operative position or across tracks G11B5/55Track change, selection or acquisition by displacement of the head G11B5/5504across tape tracks G11B5/5508Control circuits therefor G11B5/5513Specially adapted for transducing in both travelling directions of tape G11B5/5517Controlled by automatic tape drive reversing arrangement G11B5/5521across disc tracks G11B5/5526Control therefor; circuits, track configurations or relative disposition of servo-information transducers and servo-information tracks for control thereof G11B5/553Details G11B5/5534Initialisation, calibration G11B5/5539Skew adjustment G11B5/5543servo-format therefor G11B5/5547"Seek" control and circuits therefor G11B5/5552using fine positioning means for track acquisition separate from the coarse ( G11B5/5556with track following after a "seek" G11B5/556control circuits therefor G11B5/5565system adaptation for compensation of variations of physical parameters G11B5/5569details of specially adapted mobile parts G11B5/5573Details of the magnetic circuit G11B5/5578Multiple actuators addressing the same disk G11B5/5582system adaptation for working during or after external perturbation G11B5/5586Minimising seek noise G11B5/5591across drum tracks G11B5/5595Control circuits therefor G11B5/56with provision for moving the head support for the purpose of adjusting the position of the head relative to the record carrier G11B5/58with provision for moving the head for the purpose of maintaining alignment of the head relative to the record carrier during transducing operation G11B5/581maintaining desired contact or spacing by direct interaction of forces generated between heads or supports thereof and record carriers or supports thereof G11B5/582interactions in a magnetic field G11B5/583using repulsion generated by superconductors in a magnetic field G11B5/584for track following on tapes G11B5/588by controlling the position of the rotating heads G11B5/592using bimorph elements supporting the heads G11B5/5921using auxiliary signals G11B5/5922superimposed on the main signal G11B5/5923recorded in horizontal suppression internal of video frame G11B5/5925recorded in vertical suppression internal of video frame G11B5/5926recorded in separate tracks G11B5/5927Helicoidal tracks G11B5/5928Longitudinal tracks G11B5/596for track following on disks G11B5/59605Circuits G11B5/59611Detection or processing of peak/envelop signals G11B5/59616Synchronisation; Clocking G11B5/59622Gain control; Filters G11B5/59627Aligning for runout, eccentricity or offset compensation G11B5/59633Servo formatting G11B5/59638Servo formatting apparatuses G11B5/59644Acquisition or selection of servo format from a system reference G11B5/5965Embedded servo format G11B5/59655Sector, sample or burst servo format G11B5/59661Spiral servo format G11B5/59666Self servo writing G11B5/59672Servo re-writing G11B5/59677with optical servo tracking G11B5/59683for magnetoresistive heads G11B5/59688Servo signal format patterns or signal processing thereof G11B5/59694System adaptation for working during or after external perturbation G11B5/60Fluid-dynamic spacing of heads form record-carriers G11B5/6005Specially adapted for spacing from a rotating disc using a fluid cushion G11B5/6011Control of flying height G11B5/6017using capacitive measurement G11B5/6023using inductive measurement G11B5/6029Measurement using values derived from the data signal read from the disk G11B5/6035using electrostatic forces G11B5/6041using magnetic forces G11B5/6047using magnetostrictive means G11B5/6052using optical means G11B5/6058using piezoelectric means G11B5/6064using air pressure G11B5/607using thermal means G11B5/6076Detecting head-disk contact G11B5/6082Design of the air bearing surface G11B5/6088Optical waveguide in or on flying head G11B5/6094Preventing or discharging electrostatic charge build-up on the flying head G11B5/62Record carriers characterised by the selection of the material G11B5/627of leaders for magnetic tapes G11B5/633of cinematographic films or slides with integral magnetic track G11B5/64Comprising only the magnetic material without bonding agent G11B5/642self supporting magnetic material G11B5/645characterised by the film material G11B5/647containing Fe or Ni G11B5/65Characterized by its composition G11B5/653containing Fe or Ni G11B5/656containing Co G11B5/66consisting of several layers G11B5/667including a soft magnetic layer G11B5/68comprising one or more layers of magnetisable material homogeneously mixed with a bonding agent G11B5/70on a base layer G11B5/7006comprising a magnetic layer on both sides covered with non-magnetic material G11B5/7013characterised by the dispersing agent G11B5/702characterised by the bonding agent G11B5/7021containing a polyurethane or a polyisocyanate G11B5/7022containing mixtures of polyurethanes or polyisocyanates with other polymers G11B5/7023containing polyesters, polyethers, silicones, polyvinyl resins, polyacrylresins or epoxy resins G11B5/7025containing cellulosic derivates G11B5/7026Radiation curable polymers G11B5/7027Graft polymers G11B5/7028Additives G11B5/706characterised by the composition of the magnetic material G11B5/70605metals or alloys G11B5/7061with a non-magnetic core G11B5/70615containing Fe metal or alloys G11B5/70621containing Co metal or alloys G11B5/70626containing non-metallic substances G11B5/70631with a non-magnetic core G11B5/70636CrO2 G11B5/70642iron oxides G11B5/70647with a skin G11B5/70652gamma - Fe2 O3 G11B5/70657with a skin G11B5/70663Preparation processes specially adapted therefor G11B5/70668containing a dopant G11B5/70673containing Co G11B5/70678Ferrites G11B5/70684Ferro-ferrioxydes G11B5/70689Magnetite G11B5/70694Non-stoechiometric ferro-ferrioxydes G11B5/708characterised by addition of non-magnetic particles to the layer G11B5/7085non-magnetic abrasive particles G11B5/71characterised by the lubricant G11B5/712characterised by the surface treatment or coating of magnetic particles G11B5/714characterised by the dimension of the magnetic particles G11B5/716characterised by two or more magnetic layers G11B5/718at least one on each side of the base layer G11B5/72Protective coatings G11B5/722containing an anticorrosive material G11B5/725containing a lubricant G11B5/73Base layers G11B5/7305with bonding agent in the material G11B5/731without bonding agent in the material G11B5/7315substrates G11B5/732seed layers G11B5/7325layers between substrate and first magnetic recording layer other than soft magnetic layers and seed layers G11B5/733characterised by the addition of non-magnetic particles G11B5/735characterised by the back layer G11B5/738characterised by the intermediate layer G11B5/74Record carriers characterised by the form G11B5/743Patterned record carriers, wherein the magnetic recording layer is patterned into magnetic isolated data islands G11B5/746Bit Patterned record carriers, wherein each magnetic isolated data island corresponds to a bit G11B5/76Drum carriers G11B5/78Tape carriers G11B5/80Card carriers G11B5/82Disc carriers G11B5/825flexible discs G11B5/84Processes or apparatus specially adapted for manufacturing record carriers G11B5/8404manufacturing base layers G11B5/8408protecting the magnetic layer G11B5/8412treatment by ultrasonics G11B5/8416coating a support with a magnetic layer by precipitation G11B5/842Coating a support with a liquid magnetic dispersion G11B5/845in a magnetic field G11B5/848Coating a support with a magnetic layer by extrusion G11B5/85Coating a support with a magnetic layer by vapour deposition G11B5/851Coating a support with a magnetic layer by sputtering G11B5/852Orientation in a magnetic field G11B5/855Coating only part of a support with a magnetic layer G11B5/858Producing a magnetic layer by electro-plating or electroless plating G11B5/86Re-recording G11B5/865by contact "printing"