Strong suppression of the Curie temperature in the electron-doped system La1-xCexCoO3

TL;DR

This study demonstrates that electron doping in La1-xCexCoO3 thin films induces ferromagnetism across the entire doping range, but significantly suppresses the Curie temperature compared to hole-doped counterparts, likely due to reduced hybridization.

Contribution

It provides new insights into the magnetic phase diagram of electron-doped La1-xCexCoO3 and highlights the suppression of Tc related to hybridization effects.

Findings

Ferromagnetic order observed across all doping levels.

Maximum Tc around 22 K at x ≈ 0.3.

Strong suppression of Tc compared to hole-doped systems.

Abstract

We show for the system La1-xCexCoO3 (0.1 <= x <= 0.4) that it is possible to synthesize electron-doped cobaltites by the growth of epitaxial thin films. For La1-xCexCoO3, ferromagnetic order is observed within the entire doping range (with the maximum of the Curie temperature, Tc, at x ca. 0.3), resulting in a magnetic phase diagram similar to that of hole-doped lanthanum cobaltites. The measured spin values strongly suggest an intermediate-spin state of the Co ions which has been also found in the hole-doped system. In contrast to the hole-doped material, however, where Tc is well above 200 K, we observe a strong suppression of the maximum Tc to about 22 K. This is likely to be caused by a considerable decrease of the Co3d - O2p hybridization. The observed intriguing magnetic properties are in agreement with previously reported theoretical results.