Probing Intrinsic Material Conductivity in Two-Terminal Devices: A   Resistance-Difference Method
  It is generally impossible to separately measure the resistance of the functional component (i.e., the intrinsic device materials) and the parasitic component (i.e., terminals, interfaces and serial loads) in a two-terminal device. Yet such knowledge is important for understanding device physics and designing device systems. Here, we consider a case where an electric current, temperature, or magnetic field causes a small but identical relative conductivity change of the device materials. We find an exact solution to this relative change by a simple resistance-data analysis of similarly configured two-terminal devices. The solution is obtainable even if the change is quite small, say, less than 0.1%. In special cases of small relative changes in parasitic resistance, the absolute parasitic resistance is also obtainable. Our method is especially useful for studying the switching and transport characteristics of the emergent non-volatile resistance memory. 
Yang Lu and I-Wei Chen
cond-mat.mes-hall