Metal - insulator transitions in La{sub 1-x}TiO{sub 3}, 0.0 {le} x {le} 0.33. Structure - property correlations
- McMaster Univ., Hamilton (Canada)
The solid-solution system La{sub 1-x}TiO{sub 3} was investigated over the range 0 {le} x {le} 0.33, i.e., involving end members LaTiO{sub 3} and La{sub 2/3}TiO{sub 3}. X-ray single-crystal and powder neutron diffraction studies have established the structure of La{sub 2/3}TiO{sub 3} for the first time which is described in Pban with a = 5.461(1) {angstrom}, b = 5.482(1) {angstrom}, c = 7.759(3) {angstrom}. La vacancies are ordered largely in the z = 1/2 plane and Ti atoms are displaced from the centers of Ti-O octahedra toward this plane giving rise to c-axis chains consisting of two short Ti-O bonds (1.906 {angstrom}) alternating with two long Ti-O bonds (1.975 {angstrom}). The Pban structure is found for 0.25 < x < 0.33, an Ibmm structure for 0.20 < x {le} 0.25 and the Pbnm (GdFeO{sub 3} type) structure for 0 {le} x < 0.20. The compounds La{sub 2/3}TiO{sub 3} (x = 0.33) and La{sub 0.70}TiO{sub 3} (x = 0.30) are insulators, La{sub 0.75}TiO{sub 3} (x = 0.25) undergoes a metal-insulator transition and La{sub 0.80}TiO{sub 3} (x = 0.20) to La{sub 0.92}TiO{sub 3} (x = 0.08) are metallic. Electrical, magnetic and structural properties are compared with those of the closely related La{sub 1-x}Sr{sub x}TiO{sub 3} and SrTiO{sub 3-x} systems. It is also argued that oxidized forms of LaTiO{sub 3}, described previously as LaTiO{sub 3+x}, are better understood as La{sub 1-x}TiO{sub 3}. 26 refs., 15 figs., 11 tabs.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 98754
- Journal Information:
- Chemistry of Materials, Journal Name: Chemistry of Materials Journal Issue: 11 Vol. 6; ISSN CMATEX; ISSN 0897-4756
- Country of Publication:
- United States
- Language:
- English
Similar Records
Magnetic and structural studies of La{sub 1-x}Sm{sub x}TiO{sub 3} (O {le} x {le} 1)
Synthesis, structure, and characterization of Ce[sub 1[minus]x]A[sub x]TiO[sub 3] (0. 0 [le] x [le] 0. 8; A = Sr, Ba)