A heat-assisted magnetic recording (HAMR) medium has a multilayered underlayer between the heat-sink layer and the recording layer. One embodiment of the underlayer is a multilayer of a thermal barrier layer consisting essentially of MgO and TiO, and a seed layer containing MgO and nitrogen (N) directly on the thermal barrier layer, with the recording layer on and in contact with the seed layer. The interface between the thermal barrier layer and the seed layer contains Ti and N, some of which may be present as TiN to act as a diffusion barrier to prevent diffusion of the Ti into the recording layer. The Ti-containing thermal barrier layer has a higher thermal resistivity than the conventional MgO thermal barrier/seed layer and thus allows for reduced laser power to the recording layer while still achieving a high thermal gradient at the recording layer.

A heat-assisted magnetic recording (HAMR) medium has a multilayered underlayer between the heat-sink layer and the recording layer. One embodiment of the underlayer is a multilayer of a thermal barrier layer consisting essentially of MgO and TiO, and a seed layer containing MgO and nitrogen (N) directly on the thermal barrier layer, with the recording layer on and in contact with the seed layer. The interface between the thermal barrier layer and the seed layer contains Ti and N, some of which may be present as TiN to act as a diffusion barrier to prevent diffusion of the Ti into the recording layer. The Ti-containing thermal barrier layer has a higher thermal resistivity than the conventional MgO thermal barrier/seed layer and thus allows for reduced laser power to the recording layer while still achieving a high thermal gradient at the recording layer.

According to one embodiment, a printed circuit board includes a substrate and a shared pad group provided on the substrate and including a plurality of shared pads. The shared pads include a first area, a second area smaller in size than the first area, a port of which is overlap the first area and an other port of which is located to protrude from the first area to a side of another one of the shared pads, and a second side edge located on a side of another shared pad. The second pad side edge includes a first side edge defining the first area, a second side edge defining the second area and displaced on a side of another shared pad with respect to the first side edge, and a sloping side edge connecting the first side edge and the second side edge to each other.

According to one embodiment, a printed circuit board includes a substrate and a shared pad group provided on the substrate and including a plurality of shared pads. The shared pads include a first area, a second area smaller in size than the first area, a port of which is overlap the first area and an other port of which is located to protrude from the first area to a side of another one of the shared pads, and a second side edge located on a side of another shared pad. The second pad side edge includes a first side edge defining the first area, a second side edge defining the second area and displaced on a side of another shared pad with respect to the first side edge, and a sloping side edge connecting the first side edge and the second side edge to each other.

A system and method for recycling rare earth materials from dissimilar hard disk drives are provided. The system and method generally include scanning each hard disk drive, sorting and aligning each hard disk drive, rapid fastener removal or diversion to a metrology station, and the collection of separated value streams, optionally for formation into new magnetic stock. For each scanned hard disk drive having a match in an inventory database, the method includes the separation of an internal magnet from residual components. For each scanned hard disk drive lacking a match in the inventory database, the method includes generating a metrology data collection record containing the location of each fastener on multiple surfaces of the corresponding hard disk drive. The system and method are commercially scalable with the potential to generate between 600 and 700 metric tons of rare earth elements from a single processing facility annually, including neodymium for example.

The presently disclosed technology teaches integrating disc drive electronics into a transducer head. Decreased electrical transit times and data processing times can be achieved by placing the electronics on or within the transducer head because electrical connections may be made physically shorter than in conventional systems. The electronics may include one or more of a control system circuit, a write driver, and/or a data buffer. The control system circuit generates a modified clock signal that has a fixed relation to phase and frequency of a bit-detected reference signal that corresponds to positions of patterned bits on the disc. The write driver writes outgoing data bits received from an external connection to off-head electronics directly to the writer synchronized with the modified clock signal. The data buffer stores and converts digital data bits sent from the off-head electronics to an analog signal that is synchronized with the modified clock signal.

A fluorine-containing ether compound represented by Formula (1) is provided,
R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4  (1)
(In Formula (1), R.sup.1 is an alkyl group that may have a substituent, R.sup.2 is a divalent linking group bonded to R.sup.1 via an ethereal oxygen, R.sup.3 is a perfluoropolyether chain, and R.sup.4 is an end group which is different from R.sup.1-R.sup.2 and includes two or three polar groups, in which each of the polar groups is bonded to a different carbon atom, and the carbon atoms bonded to the polar groups are bonded to each other via a linking group containing a carbon atom not bonded to the polar groups.).

A fluorine-containing ether compound represented by Formula (1) is provided,
R.sup.1—R.sup.2—CH.sub.2—R.sup.3—CH.sub.2—R.sup.4  (1)
(In Formula (1), R.sup.1 is an alkyl group that may have a substituent, R.sup.2 is a divalent linking group bonded to R.sup.1 via an ethereal oxygen, R.sup.3 is a perfluoropolyether chain, and R.sup.4 is an end group which is different from R.sup.1-R.sup.2 and includes two or three polar groups, in which each of the polar groups is bonded to a different carbon atom, and the carbon atoms bonded to the polar groups are bonded to each other via a linking group containing a carbon atom not bonded to the polar groups.).

An aluminum alloy substrate for a magnetic disk including an aluminum alloy containing 0.1 to 3.0 mass % of Fe, 0.005 to 1.000 mass % of Cu, and 0.005 to 1.000 mass % of Zn, with a balance of Al and inevitable impurities, wherein in an outer peripheral surface thereof, the number of holes having maximum diameters of 10 μm or more is 200/mm.sup.2 or less, an aluminum alloy base disk for a magnetic disk and a magnetic disk, using the aluminum alloy substrate, and methods for manufacturing these.

According to one embodiment, a printed circuit board includes a base substrate, a first pad located on the base substrate, a second pad located on the base substrate alongside the first pad with respect to a first direction X with a gap therebetween and a solder resist covering the base substrate and including a cavity portion in a position overlapping the first pad and the second pad, the solder resist including a first protruding portion projecting in a second direction crossing the first direction and a second protruding portion projecting in the second direction on an opposite side to the first protruding portion, and the first protruding portion and the second protruding portion each overlap the gap, an end of the first pad on a gap side, and an end of the second pad on a gap side.