The relationship between structural variation and electrical properties in the spinel MgV_2-xTi_xO₄ (0 ≤ x ≤ 1.8) system

Polycrystalline samples of MgV_2-xTi_xO₄ (0 ≤ x ≤ 1.8) were prepared by solid-state reactions under an argon atmosphere and their electrical properties were studied. X-ray powder diffraction analysis indicated the formation of the spinel phase as the major compound. Solid solutions were formed throughout the system, as indicated by the monotonic variation of the unit-cell parameter. All the samples were semiconducting below room temperature. A minimum in the activation energy required for semiconduction was observed at x = 1.0. A change in resistivity behavior was observed when the titanium content was increased. For 0 ≤ x ≤ 1.2, the conduction behavior was interpreted as the hopping conduction of thermally activated electrons, whereas the resistivity behavior for 1.4 ≤ x ≤ 1.8 was characterized by a weak temperature dependence at-low temperatures.