Magnetism and superconductivity in the spinel system Li/sub 1-x/M/sub x/Ti/sub 2/O/sub 4/ (M = Mn/sup 2 +/, Mg/sup 2 +/)

Journal Article · Mon Aug 01 00:00:00 EDT 1988 · J. Solid State Chem.; (United States)

DOI:https://doi.org/10.1016/0022-4596(88)90173-9· OSTI ID:5998852

Lambert, P M; Harrison, M R; Edwards, P P

X-ray power diffraction measurements show that the M/sup 2 +/ cations substitute almost completely at the tetrahedral sites in the Li/sub 1-x/M/sub x/Ti/sub 2/O/sub 4/ spinel systems (M = Mn/sup 2 +/, 0 < x < 1; M = Mg/sup 2 +/, 0 < x < 0.2). The magnetic susceptibility of the Li/sub 1-x/M/sub x/Ti/sub 2/O/sub 4/ system is dominated by high-spin Mn/sup 2 +/ moments for x < 0.5 and shows ferrimagnetic ordering at low temperatures (15-55 K) for samples with higher x compositions. The occurrence of spontaneous magnetism in the Li/sub 0.4/Mn/sub 0.6/Ti/sub 2/O/sub 4/ sample is interpreted as indicating a compositionally induced metal-nonmetal transition near that composition. The titanium-titanium cation distance at the transition is 3.016(2) /Angstrom/ in excellent agreement with Goodenough's critical R/sub c/ value of 3.02 /Angstrom/ for Ti/sup 3 +/ ions. The magnetic susceptibility of the Li/sub 1-x/Mg/sub x/Ti/sub 2/O/sub 4/ system is distinguished by large Pauli susceptibilities and the Curie behavior of small concentrations of spins trapped at defect sites. The superconducting transition temperature T/sub c/ falls with increasing x and shows a strong correlation with the lattice parameter in both series. A decreasing density of states at the Fermi level resulting from increasing electron correlation and electron-lattice interactions is proposed to account for these observations. Importantly, no magnetic impurity effect on T/sub c/ is observed.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 5998852
• Journal Information: J. Solid State Chem.; (United States), Vol. 75:2
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
LITHIUM OXIDES
PHYSICAL PROPERTIES
MANGANESE OXIDES
TITANIUM OXIDES
EXPERIMENTAL DATA
MAGNETIC PROPERTIES
POWDERS
SUPERCONDUCTIVITY
X-RAY DIFFRACTION
ALKALI METAL COMPOUNDS
CHALCOGENIDES
COHERENT SCATTERING
DATA
DIFFRACTION
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
INFORMATION
LITHIUM COMPOUNDS
MANGANESE COMPOUNDS
NUMERICAL DATA
OXIDES
OXYGEN COMPOUNDS
SCATTERING
TITANIUM COMPOUNDS
TRANSITION ELEMENT COMPOUNDS
360204* - Ceramics
Cermets
&amp; Refractories- Physical Properties