Electrical Noise From Phase Separation In Pr2/3Ca1/3MnO3 Single Crystal

TL;DR

This study uses low frequency electrical noise measurements to investigate phase separation and electronic state transitions in Pr2/3Ca1/3MnO3, revealing noise characteristics linked to percolative conductivity and phase fluctuations.

Contribution

It introduces noise analysis as a tool to probe phase separation and electronic transitions in manganite single crystals, highlighting the role of manganese clusters.

Findings

High temperature noise shows 1/f dependence with Gaussian fluctuations.

Hysteretic region exhibits large non-Gaussian noise with two-level switching.

Noise behavior suggests percolative conductivity and phase fluctuations between M-F and I-CO states.

Abstract

Low frequency electrical noise measurements have been used to probe the electronic state of the perovskite-type manganese oxide Pr2/3Ca1/3MnO3 versus temperature and in the vicinity of the field-induced transition from the insulating, charge-ordered state (I-CO) to the metallic, ferromagnetic state (M-F). At high temperature we have observed a high level of the excess noise with mainly a gaussian distribution of the resistance fluctuations, and the associated power spectral density has a standard 1/f dependence. However, in the hysteretic region, where the electrical resistance depends dramatically on the sample history, we have observed a huge non-gaussian noise characterized by two level fluctuator-like switching (TLS) in the time domain. We discuss the origin of the noise in terms of percolative behavior of the conductivity. We speculate that the dominant fluctuators are manganese clusters switching between the M-F and the I-CO phases.