Syntheses and electrical properties of tetragonal tungsten bronze type solid solution Ba6 − xLaxNb10O30 + δ (x = 0, 1, 2, 3) and Sr6Nb10O30

Tetragonal tungsten bronze (TBB) type niobium compounds Sr6Nb10O30 and a solid solution series Ba6 − xLaxNb10O30 (x = 0, 1, 2, 3) were synthesized and their resistivity was measured in the temperature range 10–300 K. The Sr compound is a semiconductor, the high temperature data (100 ≤ T ≤ 300 K) for which can be fitted to the T−14 law. Ba6Nb10O30 also is a semiconductor, but with a different temperature dependency. La-substitution in the Ba compound caused a conduction mechanism to change from semiconducting (x = 0) to metallic (X ≥ 1).