Strain-dependent electrical conduction in the system NiO-CaO

Strain-dependent electrical conduction has been observed in the system NiO-CaO. _xNiO·(1 - x)CaO solid solutions are fabricated by a traditional solid-reaction method. When the 0.03NiO·0.97CaO solid solution is annealed at 1000°C, excess NiO is excluded and precipitates on the surface or intergrain layers. When compressive stress is applied to the specimen, the electrical conductivity increases with an increase in the applied stress. The magnitude of the conductivity change exceeds 50% during 15 MPa loading at 800°C. The presence of a precipitated NiO layer over the _xNiO· (1 - x)CaO phase is suggested to be the origin of the applied stress-dependent electrical conductivity.