Abstract
Single crystals of alkali-metal gallotitanogallate (AGGTO); Ax[Ga8Ga8+xTi16-xO56] (A=K, Rb, Cs) with a new type of one-dimensional tunnel structure were grown by the flux method. The best grown AGGTO crystals were obtained by slowcooling a flux melt at 1300°C using a mixture of 20mol% crystal composition of (A2O)1(TiO2)1 (Ga2O3)1 and 80 mol% flux composition of (A2O)1(MoO3)1.5. The grown crystals were fibrous form elongating the c-axis (or tunnel axis) with a length of 5-10mm and a diameter of 10-100μm. The crystal structure and its material design are described on the basis of combination of structure units of priderite and β-gallia. The characteristic IR spectra were observed as the two absorption bands of 400cm-1 and 475cm-1, and the former was assigned to a Ga (Ti)-O stretching mode and the latter to a Ga (Ti)-O-Ga(Ti) bending mode in (Ga, Ti)O6 octahedra and GaO4 tetrahedra.
