Focused Ion Beam Pt for Cryogenic Resistive Thermometry

Local temperature measurements at cryogenic temperatures are important for studying thermal effects, both classical and quantum, in nanoscale devices. Resistive thermometry is a relatively simple way to obtain these measurements. However, most metals’ electron transport saturates at low temperatures, leading to constant resistances and making them ineffective for cryogenic thermometry. An exploration of Pt thermometers, deposited using a focused ion beam (FIB) system, reveals that they are very effective for low temperature thermometry. This is believed to be because of the carbon contamination of the Pt. A detailed analysis of the dependence of composition of the contaminants on deposition parameters and its effect on thermometer performance is presented here. Through this research, it is clear that FIB Pt offers a tunable, sensitive, template-free thermometer for nanoscale, cryogenic thermometry.