Oxygen vacancy modulating inverse and conventional magnetocaloric effects coexisting in double perovskite Bi2NiMnO6-δ films

Bai, Yuebin; Xin, Wu; Zhao, Shunsheng

doi:10.1016/j.ceramint.2020.10.251

Cited by 10 publications

(1 citation statement)

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“…With the increase of Fe content, the grain boundaries of F4, F8, and F12 films gradually show a tendency of melting as shown in Figure b–d. Such melt trace of grains is considered to be caused by an increase in oxygen vacancies, , which is in good agreement with the results of XPS, Raman spectrum, and EPR analyses. We conducted EDS elemental analyses on the surfaces of Sr 2 Bi 4 Ti 5– x Fe x O 18 films and presented the percentages of related cations in the form of bar charts in the insets of Figure a–d.…”

Section: Results and Discussionsupporting

confidence: 86%

Capturing Carriers and Driving Depolarization by Defect Engineering for Dielectric Energy Storage

Zhao

Yang

Liu

et al. 2022

ACS Appl. Mater. Interfaces

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The inevitable defect carriers in dielectric capacitors are generally considered to depress the polarization and breakdown strength, which decreases energy storage performances. Distinctive from the traditional aims of reducing defects as much as possible, this work designs (FeTi ′ – Vo ••)• and (FeTi ″ – Vo ••) defect dipoles by oxygen vacancy defect engineering in acceptor doped Sr2Bi4Ti(5–x)Fe x O18 layered perovskite films with n-type leakage conductance. It is shown that oxygen vacancies effectively capture electrons (carriers) in n-type dielectrics to enhance the breakdown strength. Meanwhile, defect dipoles provide a driving field for depolarization to engineer the generation energy of domains and the domain wall energy, which effectively lowers the residual polarization P r but not at the expense of the maximum polarization P max as relaxor ferroelectric regulations. Such defect engineering effectively breaks through the limitation, in which the energy storage density suffers from the trade-off relationship between polarization and breakdown strength. The Sr2Bi4Ti4.92Fe0.08O18 film with the proper oxygen vacancy content achieves a high energy density of 110.5 J/cm3 and efficiency of 70.0% at a high breakdown strength of 3915 kV/cm. This work explores an alternative way for breakthroughs possible in the intrinsic trade-off relationship to regulate dielectric energy storage by defect engineering.

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Section: Results and Discussionsupporting

confidence: 86%