Exploring the Pb1−xSrxHfO3 System and Potential for High Capacitive Energy Storage Density and Efficiency. Issue 1 (15th October 2021)

• Record Type: Journal Article
• Authors: Acharya, Megha; Banyas, Ella; Ramesh, Maya; Jiang, Yizhe; Fernandez, Abel; Dasgupta, Arvind; Ling, Handong; Hanrahan, Brendan; Persson, Kristin; Neaton, Jeffrey B.; Martin, Lane W.
• Is Part Of: Advanced materials. Volume 34:Issue 1(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-15
• Subjects: antiferroelectrics -- dielectrics -- energy storage -- hafnate -- pulsed‐laser deposition; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adma.202105967
• Languages: English
• ISSNs: 0935-9648

Abstract

Abstract: The hafnate perovskites PbHfO3 (antiferroelectric) and SrHfO3 ("potential" ferroelectric) are studied as epitaxial thin films on SrTiO3 (001) substrates with the added opportunity of observing a morphotropic phase boundary (MPB) in the Pb1− x Sr x HfO3 system. The resulting (240)‐oriented PbHfO3 ( Pba 2) films exhibited antiferroelectric switching with a saturation polarization ≈53 µC cm −2 at 1.6 MV cm −1, weak‐field dielectric constant ≈186 at 298 K, and an antiferroelectric‐to‐paraelectric phase transition at ≈518 K. (002)‐oriented SrHfO3 films exhibited neither ferroelectric behavior nor evidence of a polar P 4 mm phase . Instead, the SrHfO3 films exhibited a weak‐field dielectric constant ≈25 at 298 K and no signs of a structural transition to a polar phase as a function of temperature (77–623 K) and electric field (–3 to 3 MV cm −1 ). While the lack of ferroelectric order in SrHfO3 removes the potential for MPB, structural and property evolution of the Pb1− x Sr x HfO3 (0 ≤ x < 1) system is explored. Strontium alloying increased the electric‐breakdown strength ( E B ) and decreased hysteresis loss, thus enhancing the capacitive energy storage density ( U r ) and efficiency (η). The composition, Pb0.5 Sr0.5 HfO3 produced the best combination of E B = 5.12 ± 0.5 MV cm −1, U r = 77 ± 5 J cm −3, and η = 97 ± 2%, well out‐performing PbHfO3 and other antiferroelectric oxides. Abstract : The structural and electrical properties of antiferroelectric PbHfO3 and "potentially" ferroelectric SrHfO3 are explored. Further, the energy‐storage properties of the solid solution Pb1− x Sr x HfO3 (0 ≤ x < 1) films are probed. An optimum strontium content is identified that leads to increased electric‐breakdown strength and decreased hysteresis‐loss in PbHfO3 resulting in concurrent enhancement of the capacitive energy storage density and efficiency.