Thermal strain induced large electrocaloric effect of relaxor thin film on LaNiO3/Pt composite electrode with the coexistence of nanoscale antiferroelectric and ferroelectric phases in a broad temperature range

Abstract

Ferroelectric/antiferroelectric thin/thick films with large electrocaloric (EC) effect in a broad operational temperature range are very attractive in solid-state cooling devices. We demonstrated that a large positive electrocaloric (EC) effect (maximum ΔT~20.7 K) in a broad temperature range (~110 K) was realized in Pb0.97La0.02(Zr0.65Sn0.3Ti0.05)O3 (PLZST) relaxor antiferroelectric (AFE) thin film prepared using a sol-gel method. The large positive EC effect may be ascribed to the in-plane residual thermal tensile stress during the layer-by-layer annealing process, and the high-quality film structure owing to the utilization of the LaNiO3/Pt composite bottom electrode. The broad EC temperature range may be ascribed to the great dielectric relaxor dispersion around the dielectric peak because of the coexistence of nanoscale multiple FE and AFE phases. Moreover, a large pyroelectric energy density (6.10 Jcm-3) was harvested by using an Olsen cycle, which is much larger than those (usually less than 10-4 Jcm-3) obtained by using direct thermal-electrical, Stirling and Carnot cycles, etc. These breakthroughs enable the PLZST thin film an attractive multifunctional material for applications in modern solid-state cooling and energy harvesting.

Phase structure analysis and pyroelectric energy harvesting performance of Ba(HfxTi1‐x)O3 ceramics

“…The corresponding schematic diagram per cycle is shown in . An intact Olsen cycle (1 → 2 → 3 → 4 → 1) consists of the following four parts . First, the electric field is increased ( E L → E H ; 1 → 2) at low isothermal values ( T L ; T L = 20°C in the work).…”

“…At present, an effective research method to evaluate the pyroelectric energy harvesting potential of pyroelectric materials is based on the Olsen cycle, which has been widely used in the study of pyroelectric effects of ferroelectric materials . For instance, Peng et al reported a large pyroelectric energy harvesting density value (6.10 J/cm 3 ) in lead lanthanum zirconate stannate titanate (PLZST) thin film. Fan et al reported a high pyroelectric energy harvesting density of 0.49 J/cm 3 at a limited temperature gradient (<60°C) for BST72/28 ceramics.…”

Effect of Au Addition on the Crystallinity and Electrical Properties of Thermally Strained LaNiO3−δ Thin Films

“…For polycrystalline ferroelectric films, silicon (Si) is most often used as a substrate in electronic devices, and tensile thermal strain existing in the films contributes to their ferroelectric properties. [11][12][13] However, for LNO films, previous investigations have shown that tensile strain has a negative effect on their conductivity. 14,15 Accordingly, the working voltage and power dissipation increase in devices in which an LNO film is used as the bottom electrode on an Si substrate.…”

Designing coexisting multi-phases in PZT multilayer thin films: an effective way to induce large electrocaloric effect

“…6 For the Pb 0.97 La 0.02 (-Zr 0.65 Sn 0.3 Ti 0.05 )O 3 thin lm, DT ¼ 20.1 K was obtained at a temperature corresponding to the antiferroelectric (AFE) phase to paraelectric phase transition. 15 Although a high working temperature may permit cooling applications in many elds, such as automotive, aerospace, or food industries, a lower working temperature is also important and can be used in on-chip refrigeration or other elds. In particular, lower working temperatures are also benecial to reduce the lms fatigue, entitling them with higher breakdown strength.…”