The present disclosure generally relates to a tape head and a tape head drive including a tape head. The tape head comprises at least one same gap verify (SGV) module comprising a plurality of write transducer and read transducer pairs. Each write transducer is coupled to writer bonding pads via writer leads, and each read transducer is coupled to reading bonding pads via reader leads. An isolation shield is disposed between the write transducer and read transducer such that the isolation shield is disposed between each writer lead and each reader lead. The isolation shield acts as a Faraday cage to reduce cross-talk between the write and read transducers. The SGV module is configured to write data to a tape using the write transducers and read verify the data written on the tape using the read transducers such that the write transducers and read transducers are concurrently operable.

A magnetic recording medium is a tape-shaped magnetic recording medium that has a recording layer including an ?-iron oxide particle. An area ratio R.sub.low (=(S.sub.low/S.sub.total)?100) of a total area S.sub.total of an SFD curve of the recording layer in a perpendicular direction and an area S.sub.low of the SFD curve in which a coercivity Hc is in a range from ?500 [Oe]?Hc?500 [Oe] is equal to or less than 5.5%.

A magnetic tape device. The angle ? formed by the axis of the element array of the magnetic head with respect to a width direction of the magnetic tape is changed during running of the magnetic tape in the magnetic tape device. In a case where a maximum value of an absolute value of a difference between a servo band spacing obtained before storage in a predetermined environment and a servo band spacing obtained after storage in the environment for a storage time T is defined as A, and T is set to a plurality of predetermined times, a medium life calculated by a linear function of A and a logarithm log.sub.e T of T, that are derived from a value of A and a value of the logarithm log.sub.e T of T obtained for each T is 5 years or longer.

An aqueous electroless nickel-phosphorous plating bath for forming an electroless nickel-phosphorous coating on an alkaline zincate coated substrate includes about 1.0 g/l to less than 5.0 g/l Ni, about 25 g/l to about 40 g/l hypophosphorous reducing agent; and 0 to about 120 g/l orthophosphite by-product. The electroless nickel-phosphorous bath with an orthophosphite concentration of up to about 120 g/l provides an electroless nickel-phosphorous deposit on the zincate coated substrate with an intrinsic stress that is more compressive than electroless nickel-phosphorous deposit provided using conventional electroless nickel-phosphorous baths.

A magnetic recording medium includes a substrate and a stacked film on the substrate and including a magnetic recording layer. An elastic modulus E.sub.sub of the substrate satisfies Equation (1) below, where h is a film thickness of the stacked film and E.sub.film is an Young's modulus of the stacked film:

E.sub.sub?(200*E.sub.film)/(6*h)(1).

A substrate for a magnetic disk includes a substrate main body having two main surfaces and an outer circumferential edge surface, and a film that is an alloy film containing Ni and P and provided on a surface of the substrate main body. A disk shape of the substrate main body has an outer diameter of 90 mm or more. A thickness T of the substrate that includes film thicknesses of sections of the film provided on the main surfaces is 0.520 mm or less. A total thickness D mm, which is a sum of the film thicknesses of the sections of the film on the main surfaces and the thickness T mm satisfy D0.0082/T0.0015. A surface roughness maximum height Rz of the film provided on the outer circumferential edge surface is smaller than that of the substrate main body at the outer circumferential edge surface.

The purpose of the present invention is to provide a magnetic recording medium capable of achieving high recording density by decreasing the bit transition width of a heat-assisted magnetic recording medium during the heat-assisted recording stage. The magnetic recording medium according to the present invention includes a non-magnetic substrate and a magnetic recording layer, wherein the magnetic recording layer includes an ordered alloy containing Fe, Pt and Ru, the ordered alloy includes x atom % of Fe, y atom % of Pt and z atom % of Ru on the basis of the total number of the Fe, Pt and Ru atoms, and the parameters x, y and z satisfy the following expressions (i)-(v): (i) 0.85x/y1.3; (ii) x53; (iii) y51; (iv) 0.6z20; and (v) x+y+z=100.

A magnetic-disk glass substrate according to the present invention is a doughnut-shaped magnetic-disk glass substrate having a circular hole provided in the center, a pair of main surfaces, and an outer circumferential end surface and an inner circumferential end surface each including a side wall surface and a chamfered surface that is formed between each main surface and the side wall surface. A measurement point is provided on the outer circumferential end surface every 30 degrees in the circumferential direction with reference to a center of the glass substrate, and when a curvature radius of a shape of a portion between the side wall surface and the chamfered surface is determined at each measurement point, the difference in the curvature radius between neighboring measurement points is 0.01 mm or less.

A magnetic-disk glass substrate has a circular center hole a pair of main surfaces and an edge surface. The edge surface has a side wall surface and chamfered surfaces interposed between the side wall surface and the main surfaces, and a roundness of an edge surface on an outer circumferential side is 1.5 m or less. Also, a midpoint A between centers of two least square circle respectively derived from outlines in a circumferential direction respectively obtained at two positions spaced apart by 200 m in a substrate thickness direction on the side wall surface on the outer circumferential side, and centers B and C respectively derived from a respective one of two chamfered surfaces on the outer circumferential side in the substrate thickness direction, are located such that a sum of respective distances between A and B, and A and C, is 1 m or less.

Disclosed is a perpendicularly magnetized film structure that uses a highly heat resistant underlayer film on which a cubic or tetragonal perpendicularly magnetized film can grow with high quality, the structure comprising any one substrate (5) of a cubic single crystal substrate having a (001) plane, or a substrate having a cubic oriented film that grows to have the (001) plane; an underlayer (6) formed on the substrate (5) from a thin film of a metal having an hcp structure, such as Ru or Re, in which the [0001] direction of the thin metal film forms an angle in the range of 42 to 54 with respect to the <001> direction or the (001) orientation of the substrate (5); and a perpendicularly magnetized layer (7) located on the metal underlayer (6) and formed from a cubic material selected from the group consisting of a Co-based Heusler alloy, a cobalt-iron (CoFe) alloy having a bcc structure, and the like, as a constituent material, and grown to have the (001) plane.