Structure, magnetic, and transport properties of Ti-substituted La{sub 0.7}Sr{sub 0.3}MnO{sub 3}
- Department of Physics, University of Missouri-Rolla, Rolla, Missouri 65409 (United States)
- Department of Physics, University of Missouri-Columbia, Columbia, Missouri 65211 (United States)
- Graduate Center for Materials Research, University of Missouri-Rolla, Rolla, Missouri 65409 (United States)
- Tata Institute of Fundamental Research, Colaba, Mumbai 400-005 (India)
Ti-substituted perovskites La{sub 0.7}Sr{sub 0.3}Mn{sub 1-x}Ti{sub x}O{sub 3} with 0{<=}x{<=}0.20, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3c) from 10 K to room temperature. At room temperature, the cell parameters a,c and the unit cell volume increase with increasing Ti content. However, at 10 K, the cell parameter a has a maximum value for x=0.10, and decreases for x>0.10, while the unit cell volume remains nearly constant for x>0.10. The average (Mn,Ti)-O bond length increases up to x=0.15, and the (Mn,Ti)-O-(Mn,Ti) bond angle decreases with increasing Ti content to its minimum value at x=0.15 at room temperature. Below the Curie temperature T{sub C}, the resistance exhibits metallic behavior for the x{<=}0.05 samples. A metal (semiconductor) to insulator transition is observed for the x{>=}0.10 samples. A peak in resistivity appears below T{sub C} for all samples, and shifts to a lower temperature as x increases. The substitution of Mn by Ti decreases the 2p-3d hybridization between O and Mn ions, reduces the bandwidth W, and increases the electron-phonon coupling. Therefore, the T{sub C} shifts to a lower temperature and the resistivity increases with increasing Ti content. A field-induced shift of the resistivity maximum occurs at x{<=}0.10. The separation of T{sub C} and the resistivity maximum temperature T{sub {rho}}{sub ,max} enhances the MR effect in these compounds due to the weak coupling between the magnetic ordering and the resistivity as compared with La{sub 0.7}Sr{sub 0.3}MnO{sub 3}.
- OSTI ID:
- 20665031
- Journal Information:
- Physical Review. B, Condensed Matter and Materials Physics, Vol. 71, Issue 1; Other Information: DOI: 10.1103/PhysRevB.71.014433; (c) 2005 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
SUPERCONDUCTIVITY AND SUPERFLUIDITY
BOND ANGLE
BOND LENGTHS
CURIE POINT
ELECTRON-PHONON COUPLING
LANTHANUM COMPOUNDS
MAGNETIZATION
MAGNETORESISTANCE
MANGANESE COMPOUNDS
MANGANESE IONS
NEUTRON DIFFRACTION
OXIDES
PEROVSKITES
SEMICONDUCTOR MATERIALS
SPACE GROUPS
STRONTIUM COMPOUNDS
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
TITANIUM
TRIGONAL LATTICES