High-temperature ferroelectricity in SrTiO$_{3}$ crystals

TL;DR

This paper demonstrates that bulk SrTiO₃ crystals exhibit stable ferroelectricity above room temperature, with switchable polarization domains up to 420K, challenging the notion that ferroelectricity in SrTiO₃ requires complex engineering.

Contribution

It reveals that bulk SrTiO₃ crystals can show high-temperature ferroelectricity without special substrate engineering, expanding understanding of ferroelectric behavior in this material.

Findings

Ferroelectric domains can be written and erased in bulk SrTiO₃ at temperatures up to 420K.

Hysteretic switching of local electric polarization observed in bulk crystals.

High-temperature ferroelectricity demonstrated without complex growth techniques.

Abstract

SrTiO$_{3}$ is known to be an incipient ferroelectric. It is thought that ferroelectric stability in SrTiO$_{3}$ is suppressed by a delicate competition with quantum fluctuation and antiferrodistortion. The ferroelectric phase can, however, be stabilized by doping, isotope manipulation and strain engineering etc. Till date ferroelectricity in SrTiO$_{3}$ thin films was observed to exist up to room temperature -- that was when the films were grown on specially engineered substrates using complex growth techniques. It was possible to write and erase ferroelectric domains on the specially engineered films at room temperature. Here, we show remarkably similar ferroelectric behavior in bulk (110) single crystals of SrTiO$_{3}$ with no special engineering well above room temperature using piezoresponse force microscopy. Hysteretic switching of local electric polarization was observed and electrically active domains could be written and erased using lithographic techniques at remarkably high temperatures up to $420K$.