Suppression of the Magnetic Phase Transition in Manganites Close to the Metal-Insulator Crossover

TL;DR

This paper investigates how the magnetic phase transition in La1-xCaxMnO3 manganites is suppressed near the metal-insulator transition, revealing a new crossover temperature and the effects of disorder on magnetic behavior.

Contribution

It introduces the concept of a crossover temperature Tf replacing TC and links the suppression of magnetic order to disorder caused by the metal-insulator transition proximity.

Findings

Suppression of magnetic phase transition near x=0.2 and x=0.5

Identification of a new crossover temperature Tf

Disorder effects disrupting magnetic homogeneity

Abstract

We report the suppression of the magnetic phase transition in La1-xCaxMnO3 close to the localized-to-itinerant electronic transition, i.e. at x = 0.2 and x = 0.5. A new crossover temperature Tf can be defined for these compositions instead of TC. Unlike in common continuous magnetic phase transition the susceptibility does not diverge at Tf and a spontaneous magnetization cannot be defined below it. We propose that the proximity to the doping-induced metal-insulator transition introduces a random field which breaks up the electronic/magnetic homogeneity of the system and explains these effects.