Magnetoresistance in Semiconducting Strontium Titanate

The weak-field magnetoresistance coefficients have been measured in niobium-doped SrTi${\mathrm{O}}_3$ at 4.2, 77, and 120°K. The results at 77 and 120°K are consistent with a conduction-band structure consisting of minima along the $〈100〉$ reciprocal axes. The phase transition at 110°K does not have a significant effect on the magnetoresistance results. It is postulated that the absence of a large piezoresistance effect in cubic SrTi${\mathrm{O}}_3$ due to the electron-transfer mechanism is a result of the small magnitude of the deformation-potential constant.