Giant 1/f noise in perovskite manganites: evidence of the percolation threshold

TL;DR

This paper reports the discovery of extremely large 1/f noise near the Curie temperature in manganites, providing evidence of a percolation transition in their ferromagnetic phase.

Contribution

It presents new evidence linking 1/f noise scaling to the percolation threshold in manganites, highlighting the role of domain size and crystallite effects.

Findings

Unprecedented 1/f noise magnitude near Tc

Scaling behavior indicates percolation transition

Resistance changes suggest domain size dependence

Abstract

We discovered an unprecedented magnitude of the 1/f noise near the Curie temperature Tc in low-Tc manganites. The scaling behavior of the 1/f noise and the resistance provides strong evidence of the percolation nature of the ferromagnetic transition in the polycrystalline samples. The step-like changes of the resistance with temperature, observed for single crystals, suggest that the size of the ferromagnetic domains depends on the size of crystallites.