Simple 4-segment thermal cycling pyroelectric measurement protocol for differentiating between ferroelectric and non-ferroelectric materials

TL;DR

This paper introduces a 4-segment thermal cycling protocol for pyroelectric measurements that effectively distinguishes true ferroelectric signals from artefacts, improving the reliability of ferroelectricity detection in complex materials.

Contribution

A novel 4-segment thermal cycling protocol for pyroelectric measurements that isolates irreversible thermally stimulated currents from reversible polarization signals.

Findings

The protocol successfully differentiates ferroelectric from non-ferroelectric responses.

Experimental verification on prototype and complex materials shows absence of spontaneous polarization.

The method enhances accuracy in identifying true ferroelectric phases.

Abstract

The rare-earth chromates (RECrO$_3$) and manganites (REMnO$_3$) where, RE = Eu, Y, Dy, Ho, Gd are constantly under scrutiny in search of room temperature magnetoelectric multiferroics. However, the artefacts and undesirable signal in some of the measurements pose a severe challenge in confirming the ferroelectric (FE) phase, especially in reference to pyroelectric current measurement technique. In this regard, we propose a simple modified approach to pyroelectric current measurement named as 4-segment thermal cycling protocol. This protocol assists in isolating the elusive, irreversible thermally stimulated current from the currents associated with spontaneous and reversible nature of the electric polarization in FE phase. In order to explain working principle of the protocol, we have compared simulated response of two hypothetical materials; an FE material free of space charges and a paraelectric material possessing only space charges. Further, we experimentally verify these new protocols in a single crystal of prototype ferroelectric material, Glycine Phosphite. This report primarily focuses on detailed investigation of ferroelectricity using the proposed protocol in two polycrystalline materials, HoCrO$_3$ and DyFe$_{0.5}$Mn$_{0.5}$O$_3$ where, the former has been reported to be multiferroic earlier. Our elaborative and careful approach to pyroelectric studies expound on the absence of reversible spontaneous electric polarization at temperature ranges tested in both, HoCrO$_3$ and DyFe$_{0.5}$Mn$_{0.5}$O$_3$.