A design of simple clamp type pressure apparatus utilized for measurements of magnetic susceptibility and electrical resistivity at low temperatures is presented. The cell consists of WC piston and Be–Cu cylinder which was autofrettage processed, and sample cavity consists of a teflon bucket and an electrode plug. In a temperature range from 300 K down to 77 K, pressure was determined by manganin gauge which was calibrated by Bi I→II transition pressure at room temperature and also the temperature dependence of pressure coefficient of manganin resistance was taken into account. As a result, the cell was capable of generating hydrostatic pressures up to 30 kbar at room temperature and at least up to 25 kbar at 4.2 K.

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We discuss the possibility of attaining more than 1 Gb/in 2 recording in helical scanning tape storage system based on obliquely oriented metal evaporated tapes. A demonstration of 1 Gb/in 2 recording using an inductive MIG type head is described. Other experimental results show that the obliquely oriented Co-O tapes are endowed with recording resolution potential beyond several Gb/in 2 , but playback signal-to-noise challenges still remain. Applying more sensitive magneto-resistive heads in the helical scanning tape system requires significant innovation in the system to overcome crucial issues of contact recording as well as re-optimization of the magnetic properties of the tape.Index Terms-Co-O, helical scanning tape system, metal evaporated tape, oblique orientation.

As an alternative method for the servo track writing of hard disk drives (HDDs), a magnetic contact duplication method by using a lithographically patterned master disk has been proposed and investigated. On the master disk, magnetic film pattern according to the information signal to be printed on slave disks is provided by a lithography technique. In this method, unlike the anhysteretic process of tile conventional contact duplication method for magnetic tapes, the master inlormation never disappears when a large external field is applied to the master while printing. This duplication method, as we call the Printed Media technology, can provide a very effective and inexpensive lump-sum servo track writing method ror HDDs.