Low energy excitations in crystalline perovskite oxides: Evidence from noise experiments

TL;DR

This study investigates low energy excitations in crystalline perovskite oxides through noise measurements, revealing localized excitations and tunneling two-level systems that influence noise behavior at cryogenic temperatures.

Contribution

It provides experimental evidence of localized excitations and tunneling two-level systems in crystalline perovskite oxides using noise analysis at low temperatures.

Findings

Localized excitations with activation energy ~70-80 meV identified.

Peak in noise observed at 35-40K.

Tunneling two-level systems detected below 30K.

Abstract

In this paper we report measurements of 1/f noise in a crystalline metallic oxide with perovskite structure down to 4.2K. The results show existence of localized excitations with average activation energy $\approx$ 70-80 meV which produce peak in the noise at T $\approx$ 35-40K. In addition, it shows clear evidence of tunnelling type two-level-systems (as in glasses) which show up in noise measurements below 30K.