Abstract:
1,203,973. Yttrium iron garnets. WESTERN ELECTRIC CO. Inc. 14 Nov., 1967 [15 Nov., 1966], No. 51783/67. Heading CIA. [Also in Divisions H1 and H4] Crystals of Y 3-x M 1 x Fe 5-y M 11 y O 12 garnet (where M 1 is a trivalent rare earth Nos. 57-71, M 11 is Ga and/or Al, x is 0-0À3, and y is 0-1.25) are grown by placing a seed crystal and a nutrient mass in a closed vessel in a 10-25 M solution of KOH in H 2 O or D 2 O, heating the solution to at least 350‹ C. while under a pressure exceeding the critical pressure, and maintaining a temperature difference between the seed and the mass of at least 5‹ C. The temperature is preferably 350-425‹ C., the pressure 8000-35000 psi, and the temperature difference 10-50‹ C. The seed crystal orientation may be (100), (211), (111) or (110). The nutrient mass may be a mixture of the oxides, which may be sintered, or crystals grown hydrothermally under maximum growth conditions. The vessel may be Pt lined and may be filled to 70-95% of its volume before heating. A baffle may be placed between the nutrient mass in the bottom of the vessel and the crystals suspended above, to maintain the temperature difference.
Abstract:
1,243,021. Rare earth orthoferrites. WESTERN ELECTRIC CO. 15 Aug., 1968 [15 Aug., 1967], No. 39102/68. Heading C1A. [Also in Divisions H1 and H3] Crystals of RFeO 3 (where at least 80% of the R atoms comprise at least one of Y, Sm, Eu, Gd, Tb Dy, Ho, Er, Tm and Yb, and 0-20% of the R atoms comprise at least one of La, Ce, Pr, and Nb) are grown by placing a seed crystal and a nutrient mass in a closed vessel in a 10-25M aqueous solution of KOH, heating the solution to at least 300‹ C. while under a pressure exceeding the critical pressure, and maintaining a temperature difference between the seed and the mass of at least 5‹ C. The temperature is preferably 350-425‹ C., the pressure 8000-35,000 p.s.i., and the temperature difference 10-50‹ C. The seed crystal is orthorhombic and may be TbAlO 3 ; its orientation is preferably (110) or (001). The nutrient mass may be a mixture of oxides, which may be sintered, or crystals grown by flux methods. The vessel may be Pt lined and may be filled to 70-95% of its volume before heating. A baffle may be placed between the nutrient mass in the bottom of the vessel and the crystals suspended above, to maintain the temperature difference. The + 3 valence state of La and Eu may be maintained by the presence of H 2 and O 2 respectively. In the examples, R was Yb, Sm/Er, Y, Ho, and Tb. The product is antiferromagnetic.
Abstract:
Zinc oxide crystals are grown from a solution by immersing a seed crystal of ZnO and a mass of nutrient ZnO in an aqueous medium containing lithium ions and the hydroxide of another alkali metal, or the hydroxide of an alkaline earth metal, or a mixture of said hydroxides, the lithium ion and the metal hydroxide having concentrations of 0.1 to 4.0 molal and 2 to 8 molal respectively, and heating said aqueous medium to a temperature of at least 300 DEG C. at a pressure of at least 3200 p.s.i. while maintaining the temperature of the nutrient mass from 5 DEG to 100 DEG C. above that of the growth region. The apparatus used may be a pressure-temperature bomb with casing 10 sealed by cover 11 and plunger 12. Disc 14 and plunger 12 seal liner 13, which is of a noble metal, say Ag, as is lip 15. Growth seed 16 is suspended by Ag wire 19 and separated by baffle 18 from nutrient mass 17 of nutrient ZnO particles. Solution 20 contains lithium ions and the hydroxides, specified sources being CH3CO2Li, Li2B4O7, lithium citrate, HCO2Li, LiOH, LiNO3, (CO2)2Li2, Li2SO4 and lithium halides and NaOH, KOM, CsOH, RbOH, Sr(OH)2 and Ba(OH)2 respectively,