Dielectric response of the charge-ordered two-dimensional nickelate La1.5Sr0.5NiO4

TL;DR

This study investigates the dielectric properties of La1.5Sr0.5NiO4, revealing high intrinsic dielectric constants and a temperature-dependent maximum linked to charge-order pattern rearrangements.

Contribution

It provides new insights into the dielectric behavior of charge-ordered nickelates and clarifies the influence of experimental factors on measured dielectric properties.

Findings

High intrinsic dielectric constant observed.

Dielectric constant peaks during charge-order rearrangement.

Charge-order pattern changes are linked to dielectric response.

Abstract

We are reporting the dielectric response of La1.5Sr0.5NiO4, a system that presents a charge-ordered state above room temperature and a rearrangement of its charge-order pattern in the temperature region 160-200 K. A careful analysis of the role of the electric contacts used, sample thickness and grain size on the experimental data allows us to determine that this material exhibits high values of intrinsic dielectric constant. The variation of the dielectric constant with temperature shows a maximum in the region of the rearrangement of the charge-order pattern, which constitutes an evidence of the link between both phenomena.