Preparing nickel ferrite single crystals on a monocrystalline substrate

摘要

A powdered mixture 7 of NiCO3 and Fe2O3 of particle size less than 5 m is blown by oxygen on to the single crystal base 2 of BaCo2Fe16O27 in the furnace at a temperature of 1325 DEG C. so as to form a detachable crystal layer not more than 200 m thick. Crystals of thickness 300 m may be formed by several deposition steps. Powdered nickel ferrite or barium titanate may be deposited on substrates which can comprise SrFe12O19, BaFe12O19, or on previously formed substrates of the material to be deposited. The powdered layer may be defracted from a suspension in a liquid.ALSO:A compound to be crystallized or a mixture of substances which react to form the desired compound of particle size not greater than 5 microns is applied in a layer not more than 200 microns thick on a sulstrate of the compound or a sulstrate with whose crystal structure it can be rationally linked and both are heated to a temperature within the recrystallization range of the compound so as to form a single layer crystal which can be separated. To obtain larger crystals the process can be repeated several times. The powder may be deposited from a suspension or may be blown on by means of a gas stream as described in relation to the apparatus of Fig. 1 (not shown).