Self-Assembled Room Temperature Multiferroic BiFeO3-LiFe5O8 Nanocomposites

TL;DR

This paper reports the development of a new room-temperature multiferroic nanocomposite made of BiFeO3 and LiFe5O8, revealing how Li doping induces phase separation and enhances multiferroic properties, supported by experimental imaging and first principles calculations.

Contribution

It introduces a novel self-assembled multiferroic nanocomposite at room temperature with insights into Li doping effects and phase formation mechanisms.

Findings

Li doping favors LFO secondary phase formation

Multimodal imaging maps phase separation and ferroic properties

First principles calculations support phase energetics understanding

Abstract

Multiferroic materials have driven significant research interest due to their promising technological potential. Developing new room-temperature multiferroics and understanding their fundamental properties are important to reveal unanticipated physical phenomena and potential applications. Here, a new room temperature multiferroic nanocomposite comprised of an ordered ferrimagnetic spinel LiFe5O8 (LFO) and a ferroelectric perovskite BiFeO3 (BFO) is presented. We observed that lithium (Li)-doping in BFO favors the formation of LFO spinel as a secondary phase during the synthesis of LixBi1-xFeO3 nanoceramics. Multimodal functional and chemical imaging methods are used to map the relationship between doping-induced phase separation and local ferroic properties in both the BFO-LFO composite ceramics and self-assembled nanocomposite thin films. The energetics of phase separation in Li doped BFO and the formation of BFO-LFO composites is supported by first principles calculations. These findings shed light on Li-ion role in the formation of a functionally important room temperature multiferroic and open a new approach in the synthesis of light element doped nanocomposites.