# Niobium nitride thin films for very low temperature resistive thermometry

## TL;DR

This paper explores niobium nitride thin films for highly sensitive resistive thermometry at ultra-low temperatures, demonstrating calibration, tunability, and applications below 30 mK with low impedance.

## Contribution

It introduces a method for using NbN thin films for precise low-temperature measurements, including calibration and tunability of the temperature range.

## Key findings

- High sensitivity in temperature detection via resistance changes.
- Tunable nitrogen content adjusts optimal temperature range.
- Successful application below 30 mK with low electrical impedance.

## Abstract

We investigate thin film resistive thermometry based on metal-to-insulator-transition (niobium nitride) materials down to very low temperature. The variation of the NbN thermometer resistance have been calibrated versus temperature and magnetic field. High sensitivity in tempertaure variation detection is demonstrated through efficient temperature coefficient of resistance. The nitrogen content of the niobium nitride thin films can be tuned to adjust the optimal working temperature range. In the present experiment, we show the versatility of the NbN thin film technology through applications in very different low temperature use-cases. We demonstrate that thin film resistive thermometry can be extended to temperatures below 30 mK with low electrical impedance.