TY - JOUR
T1 - Electrocaloric Effect of Perovskite High Entropy Oxide Films
AU - Son, Yeongwoo
AU - Zhu, Wanlin
AU - Trolier-McKinstry, Susan E.
N1 - Funding Information:
The authors gratefully acknowledge support from National Science Foundation through the Pennsylvania State University Materials Research Science and Engineering Center DMR‐2011839. The authors would also like to acknowledge Beth Jones and Nichole Wonderling for the target preparation and discussion on XRD peak analysis, respectively.
Publisher Copyright:
© 2022 Wiley-VCH GmbH.
PY - 2022/12
Y1 - 2022/12
N2 - This paper describes two perovskite high entropy oxide (PHEO) compositions: Pb(Hf0.2Zr0.2Ti0.2Nb0.2Mn0.2)O3 (Mn PHEO) and Pb(Hf0.2Zr0.2Ti0.2Nb0.2Al0.2)O3 (Al PHEO). Powders are prepared by conventional solid state sintering by first pre-reacting the B-site oxides, then adding PbO. Phase pure Mn PHEO powder is obtained following calcination of the mixed powders at 750 °C for 240 min; however, secondary phases persisted in Al PHEO for heat treatments from 750 °C to 1200 °C. The Mn PHEO undergoes an entropy-driven phase transformation. Thin films of these compounds are synthesized by pulsed laser deposition (PLD) on a lead zirconate titanate seed layer on Pt-coated SiO2/Si. The dielectric response of the Mn PHEO films show some contribution from space charge polarizability; in contrast, the Al PHEO films show a slim ferroelectric hysteresis loop and relaxor-like characteristics. The Al PHEO has a dielectric permittivity of ≈2000 with a loss tangent <0.05 from 100 Hz to 100 kHz; it has a dielectric maximum at 105 ± 0.5 °C and a Burns’ temperature of 234 ± 0.5 °C. Indirect measurements based on the Maxwell-relations yielded a maximum electrocaloric temperature change of 8.4 K at 180 °C under the applied electric field of 1186 kV cm−1.
AB - This paper describes two perovskite high entropy oxide (PHEO) compositions: Pb(Hf0.2Zr0.2Ti0.2Nb0.2Mn0.2)O3 (Mn PHEO) and Pb(Hf0.2Zr0.2Ti0.2Nb0.2Al0.2)O3 (Al PHEO). Powders are prepared by conventional solid state sintering by first pre-reacting the B-site oxides, then adding PbO. Phase pure Mn PHEO powder is obtained following calcination of the mixed powders at 750 °C for 240 min; however, secondary phases persisted in Al PHEO for heat treatments from 750 °C to 1200 °C. The Mn PHEO undergoes an entropy-driven phase transformation. Thin films of these compounds are synthesized by pulsed laser deposition (PLD) on a lead zirconate titanate seed layer on Pt-coated SiO2/Si. The dielectric response of the Mn PHEO films show some contribution from space charge polarizability; in contrast, the Al PHEO films show a slim ferroelectric hysteresis loop and relaxor-like characteristics. The Al PHEO has a dielectric permittivity of ≈2000 with a loss tangent <0.05 from 100 Hz to 100 kHz; it has a dielectric maximum at 105 ± 0.5 °C and a Burns’ temperature of 234 ± 0.5 °C. Indirect measurements based on the Maxwell-relations yielded a maximum electrocaloric temperature change of 8.4 K at 180 °C under the applied electric field of 1186 kV cm−1.
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U2 - 10.1002/aelm.202200352
DO - 10.1002/aelm.202200352
M3 - Article
AN - SCOPUS:85138267636
SN - 2199-160X
VL - 8
JO - Advanced Electronic Materials
JF - Advanced Electronic Materials
IS - 12
M1 - 2200352
ER -