Akinori Katsui

Single Crystal Growth of Ba(Pb, Bi)O3 from Molten KCl Solvent

A flux method using KCl as a solvent is proposed for the growth of Ba(Pb, Bi)O3 single crystals. The single crystals are obtained from a mixture of polycrystalline BaPb0.9Bi0.1O3 and KCl. The Meissner effect results and four-probe electrical resistance measurements indicate that the as-grown crystals are superconducting with a critical onset temperature of 10.2 to 10.8 K.

Single Crystal Growth of Superconducting BaPb1-xBixO3 from PbO2–Bi2O3–BaPbO3 Solution

Single crystals of superconducting BaPb1-xBixO3 of mm-size are obtained by slowly cooling PbO2–Bi2O3–BaPbO3 solution. It is shown from Meissner effect results that the as-grown crystals are superconducting and the critical temperature is in the temperature range from 6.3 to 10.8 K, dependent on starting composition and growth condition.

LEC growth of GaSb single crystals using boric oxide.

The Liquid Encapsulated Czochralski (LEC) technique using low viscosity B2O3 containing Na2AlF6 as an encapsulant is proposed. A detail of the growth technique is described and GaSb single crystals are prepared. Mass spectroscopic analysis and Hall coefficient measurements are performed for the grown crystal and the results are compared with those for the charged material.

Magnetooptical memory experiments on a rotating Mn-Cu-Bi disk medium

A thin film of a new magnetooptical memory medium, Mn-Cu-Bi, was prepared on a glass disk and their dynamic memory characteristics were examined with an experimental rotating disk exerciser. The Curie temperature of the medium was about 200°C. Curie-point writing was made on it. The written information was read by the Kerr effect. The Kerr rotation was ±1.3° at an Ar ion laser wavelength of 5145 A, where the Kerr rotation of the medium was made maximum by an SiO overcoating. For track selection, a moving coil with a linear motion air bearing, whose shaft was rectangular in form, was used. By utilizing a laser for the light source of a moire fringe measurement technique, an accurate track access was made possible. The accuracy was within 1 μm and the track-to-track transfer time was about 5 ms. Writing and reading were accomplished under computer control with the direct memory access mode. A 5.09 × 10-6medium error rate without error correction was obtained for a 2.5 × 105bit/cm2packing density at a data transfer rate of 0.5 MHz.

Preparation of Ferromagnetic MnCuBi Thin Films by an rf-Sputtering

An rf-sputtering technique has been investigated for the preparation of ferromagnetic MnCuBi thin films. The films are amorphous upon deposition and postdeposition annealing is required in order to crystallize them. The optimum substrate temperature for complete crystallization ranges between 90 and 150°C. In the 380 A thick films on a fused quartz substrate kept at 90°C, complete magnetization orientation normal to the film plane is realized. These films have a Curie temperature of 160°C and a room-temperature polar Faraday rotation of 2×105 degrees/cm at a wavelength of 6328 A. A preliminary thermomagnetic writing experiment on the film was conducted.