Heating-compensated constant-temperature tunneling measurements on stacks of Bi2Sr2CaCu2O8+x intrinsic junctions

In highly anisotropic layered cuprates such as Bi2Sr2CaCu2O8+x tunneling measurements on a stack of intrinsic junctions (IJs) in a high-bias range are often susceptible to self-heating. In this study we monitored the temperature variation of a stack (“sample stack”) of IJs by measuring the resistance change of a nearby stack of IJs, which was strongly thermal coupled to the sample stack. We then adopted a proportional-integral-derivative scheme incorporated with a substrate-holder heater to compensate the temperature variation. This in situ temperature monitoring and controlling technique allows one to get rid of spurious tunneling effects arising from the self-heating.