Interfacial Phase Competition Induced Kondo-like Effect in Manganite-insulator Composites

TL;DR

This study investigates the low-temperature resistivity upturn in manganite-insulator composites, attributing it to interfacial magnetic phase competition and reconstruction, supported by simulations and resistor-network modeling.

Contribution

It introduces a physical mechanism linking interfacial magnetic phase competition to the Kondo-like resistivity upturn in manganite-insulator composites.

Findings

Interfacial magnetic phase reconstruction causes resistivity upturn.

Monte Carlo simulations reveal weak antiferromagnetic tendencies at interfaces.

Resistor-network model reproduces the low-temperature resistivity behavior.

Abstract

Kondo-like effect, namely the upturn of resistivity at low temperatures, has been observed in perovskite manganite when nonmagnetic insulators were doped as the secondary phase. In this paper, the low-temperature resistivity upturn effect was argued to be originated from the interfacial magnetic phase reconstruction. Heisenberg spin lattices have been simulated using Monte Carlo method to reveal the phase competition around the secondary phase boundary, namely the manganite-insulator boundary behaves a weak antiferromagnetic tendency. And the resistor-network model based on the double-exchange conductive mechanism indeed reproduces the low-temperature resistivity upturn effect. Our work provide a reasonable physical mechanism to understand novel transport behaviors in micro-structures of correlated electron systems.