Periodicity-dependence of the ferroelectric properties in BiFeO3/SrTiO3 multiferroic superlattices

TL;DR

This study investigates how the ferroelectric properties of BiFeO3/SrTiO3 superlattices depend on their periodicity, revealing reduced leakage currents and stable polarization in certain configurations.

Contribution

It demonstrates the periodicity-dependent ferroelectric behavior in BiFeO3/SrTiO3 superlattices, highlighting reduced leakage and improved polarization stability compared to single-layer films.

Findings

Leakage current decreases with increased periodicity.

Intrinsic polarization hysteresis observed in specific periodicities.

Leakage dominated by space charge limited conduction.

Abstract

Artificial superlattices of (BiFeO3)m(SrTiO3)m (m= 1 to 10 unit cells) consisting of multiferroic BiFeO3 and insulating SrTiO3 layers were fabricated on (100)-oriented SrTiO3 substrates by pulsed laser ablation. The remnant polarization and leakage current behavior were studied varying the periodicity (8-80A) of the superlattice. The leakage current was reduced by few orders of magnitude on increase of periodicity compared to single layer BiFeO3 thin films. Reduced leakage and intrinsic polarization hysteresis was observed and was confirmed by PUND analysis for periodicities in the range 20-60A. The leakage current was observed to be dominated by space charge limited conduction