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Unusual substitutional and interstitial solid solutions were observed in (1−x)Ba(Zr0.35Ti0.65)O3-xZnO thin films, where one Zn2+ cation substituted one B-site Zr4+/Ti4+ site and two Zn2+ cations substituted one A-site Ba2+ site simultaneously. Such a hybrid solid solution with an appropriate ZnO content remarkably increases both the electric breakdown strength (Eb) by widening the bandgap and the energy storage efficiency (η) by suppressing the hysteresis of the ferroelectric loop. As a result, the films with x = 0.2 show superior energy storage performance with a recoverable energy storage density (Wrec) of 130.3 J/cm3 and η of 89.1%. This work confirms the feasibility of forming an unconventional hybrid solid solution, which may shed light on further work on perovskite oxides with improved ferroic functionalities. [ABSTRACT FROM AUTHOR]

Transparent conductive oxides have attracted extensive attentions as a promising candidate for next-generation display materials. As a substitute for indium tin oxide, BaSnO3-based materials have been widely investigated with the improvement of electrical resistivity and optical transparency. Here, the effects of diverse rare-earth ions (R = La, Nd, Sm, Er) doping on the structural, electrical, and optical properties of RxBa1−xSnO3 films are systematically studied. The rare-earth ion doping improves the crystallinity of epitaxial RxBa1−xSnO3 films. And a rule for electrical performance optimization is revealed that the resistivity and metal-semiconductor transition temperature increase with increased atomic number of rare-earth ions. Further optimized composition for LaxBa1−xSnO3 is realized at x = 5% with the minimum resistivity of 0.31 mΩ cm. Moreover, all RxBa1−xSnO3 films exhibit a high transparency of greater than 90% in the visible region. This work demonstrates that among these four rare-earth ion doping, La-doping is the most effective approach to optimize the comprehensive properties of BaSnO3-based transparent conductive films. [ABSTRACT FROM AUTHOR]

Relaxor property plays a key role in determining energy storage performance of dielectric capacitor. The usual method to improve relaxor property is to form substitutional solid solution. Here an unusually substitutional and interstitial hybrid perovskite solid solution 0.8(Ba0.85Ca0.15Zr0.1Ti0.9O3)‐0.2ZnO (BCZT:Zn) is designed, where one Zn2+ occupies B‐site and two Zn2+ share one A‐site of perovskite structure, and fabricated its epitaxial thin films. Compared to BCZT films, BCZT:Zn films have increased c/a ratio which leads to enhanced maximum polarization Pmax, wide band gap therefore high electrical breakdown strength EBDS, and enhanced relaxor degree thus suppressed remanent polarization Pr. As the results, dramatically improve energy storage property with the recoverable energy storage density Wrec of 75.9 J cm−3 and the energy storage efficiency η of 76.7% are obtained in BCZT:Zn films. This work not only provides a high performance relaxor ferroelectric material, but also impacts some new thinking to optimize die/ferro/piezoelectric properties by forming hybrid solid solutions. [ABSTRACT FROM AUTHOR]

Magnetic compounds with significant and temperature-insensitive magnetoresistance are quite promising for device applications. Here, we intentionally doped different amounts (0.025-0.1) of Co into epitaxial (La0.7Sr0.3)MnO3 thin films. The evolution of electrical, magnetic, magneto-transport, and valence state of this series of Co-doped (La0.7Sr0.3)MnO3 have been systematically characterized. Remarkably, the magnetoresistance in 0.1Co-doped (La0.7Sr0.3)MnO3 can reach significantly 35% within an extremely large temperature window (from 40 to 200 K). Other Co-doped epitaxial (La0.7Sr0.3)MnO3 thin films show similar sharp MR-peaks around Curie temperature as that in (La0.7Sr0.3)MnO3. The evolution of magnetic and magneto-transport properties of Co-(La0.7Sr0.3)MnO3 films can be explained by antiferromagnetic coupling induced by paramagnetic/low-spin Co3+(Co2+) ions in (La0.7Sr0.3)MnO3. Our work demonstrates that doping paramagnetic/low-spin Co into manganites is an effective way to optimize their magneto-transport properties. [ABSTRACT FROM AUTHOR]

A series of layered n-ABO3-doped Aurivillius structures Bi4Ti3012 (BTO) thin films are synthesized on (001) SrTiO3 (STO) substrates by pulsed laser deposition, where n represents the number of ABO3 perovskite. X-ray diffraction substantiates that these films have expected layered Aurivillius structures. Furthermore, the microstructure of these samples is "systematically" characterized by transmission electron microscopy. It is found that the structure of n-STO-doped BTO becomes unstable when n is equal to 3, as revealed by the occurrence of intergrowth. Similar phenomenon is observed in n-LaFeO3-doped BTO; the layered Aurivillius structure is totally collapsed in the case of n as high as 2.5. In contrast, 3-BiFeO3-doped BTO still keeps perfect Aurivillius structure. The above-observed structural stabilities of these materials are explained by the theoretical formation enthalpy calculated by the density functional theory. This work provides the necessary information to explore the multifunctionality based on Aurivillius n-ABO3-BTO oxides. [ABSTRACT FROM AUTHOR]

Abstract: To investigate temperature-dependent ferroelectric and dielectric properties of ferroelectric films, Bi3.25La0.75Ti3O12 (BLT) thin films were prepared on Pt-coated silicon substrates by pulsed laser deposition. The ferroelectric and dielectric behaviors have been studied in a wide temperature range from 80K to room temperature. The saturated polarization (P sat) decreases with decreasing temperature and decreasing electric field, whereas remnant polarization (P r) shows a more complex temperature dependence. These results, which can be well explained based on a temperature-dependent charged defects–domain wall interaction model, might be helpful for further understanding the domain switching behavior. Based on these results, an alternative way to investigate temperature-dependent ferroelectric fatigue is proposed and experimentally carried out. The measured fatigue rate is found to be linearly dependent on temperature, consistent with the report on Pb(Zr,Ti)O3 films. Temperature-dependent dielectric measurements of the films further confirm the above explanation. [Copyright &y& Elsevier]

Thin films of Bi3.25La0.75Ti3O12 (BLT) were fabricated by pulsed-laser deposition. The ferroelectric fatigue and Raman measurements were carried out on the as-prepared, postannealed in air and postannealed in oxygen BLT films (BLT-1, BLT-2 and BLT-3, respectively). It was revealed that the BLT-2 films have the weakest fatigue-resistance and highest frequency shifted Raman vibration modes, indicating the highest oxygen vacancy concentration in the BLT-2 films. Based on the BLT-2 films, the temperature-dependent effect of oxygen vacancy on polarization switching is investigated. Generally, the coercive field (Ec) increases while the switched polarization (Ps) decreases monotonically with decreasing temperature. However, the remnant polarization (Pr) increases when the temperature decreases from 300 to 167K, then decreases with further decreasing temperature. The results can be well explained using a model based on the temperature-dependent depth and shape of the domain wall-defect interaction potential well. [Copyright &y& Elsevier]

B-site Ti-substituted Bi1.5Zn1.0Nb1.5O7 (Bi1.5Zn1.0Nb1.5-xTixO7, x=0, 0.05, and 0.10) thin films have been fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. The x-ray diffraction and scanning electron microscopy measurements show that the films have a single phase and are well crystallized and homogeneous. Dielectric properties are investigated as function of temperature and frequency. It is found that the Ti substitution increases the dielectric constant. At 10 kHz, the room temperature dielectric constant and loss tangent ([variant_greek_epsilon], tan δ) are (163, 0.006), (182, 0.014), (197, 0.010) for the films with x=0, 0.05, and 0.10, respectively. In a wide temperature and frequency range (-100 °C∼50 °C, 1 kHz∼1 MHz), the dielectric constant is almost constant. However, below -100 °C, a dielectric relaxation depending on Ti content is observed. The relationship between structure and property of this thin film system is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Double perovskite Sr2Fe10/9Mo8/9O6 films with different thicknesses have been prepared on (111)-SrTiO3 substrates by pulsed laser deposition in flowing N2 atmosphere. The X-ray diffraction indicates the films have no impurity phases and are (111) oriented. The epitaxy and local Fe/Mo ordering are confirmed by high resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED). Mixed valence states of interior Fe and Mo cations are observed by the x-ray photoelectron spectroscopy. Interestingly, the films show significantly thickness-dependent magnetization properties: at 10K, the films show the saturated magnetization of 2.30μB/f.u. (formula unit), 1.12μB/f.u., and 0.50μB/f.u., respectively. On the other hand, the thickest film shows a magnetoresistance of −13% at 120K whereas other two samples show considerably higher resistivity and neglectable MR. The thickness effects on microstructure and properties have been discussed in detail. [Copyright &y& Elsevier]

By using pulsed laser deposition, Ba 0.95 La 0.05 PbO 3 (BLPO) thin films with different substrate temperatures (550–750 °C) and oxygen pressures (5–20 Pa) were prepared on SrTiO 3 (100) substrates. The charge valences of Ba and Pb cations in all the films are determined to be +2 and +4 by x-ray photoelectron spectroscopy. However, surface roughness of the films doesn’t keep unchanged, it increases with increasing temperature and oxygen pressure. The resistivity is significantly affected by substrate temperature and oxygen pressure, which increases with the former and decreases with the latter. Especially, the films deposited under 600 °C and 10 Pa oxygen pressure show metallic transport behavior with nearly temperature-insensitive values, as evidenced by the resistivity of 6.24×10 −5 Ω m and 5.41×10 −5 Ω m at 300 K and 15 K, respectively. Based on the structure and transport measurements, the optimized deposition conditions are determined to be close to 600 °C and 10 Pa. This work may provide some helpful clues for further work on tuning properties of BLPO films. [ABSTRACT FROM AUTHOR]

A novel ferromagnetic triple perovskite Sr3CrFeMoO9 was designed and ultrathin films were fabricated. The films are highly strained, with a sharp film/substrate interface. The valences of the Cr, Fe and Mo cations are +3, +3 and +6, respectively. Well-saturated ferromagnetic hysteresis loops are observed at room temperature and 10K, and the Curie temperature should be higher than 400K, as indicated by the temperature–magnetization curve. The films show semiconductor-like behavior with almost negligible magnetoresistance. The possible spin configuration is analyzed based on experimental results. [ABSTRACT FROM AUTHOR]

Highlights: [•] Systematically and comparative microstructure analysis for the SrIrO3 thin films. [•] Meta-stable orthorhombic SrIrO3 phase was obtained under normal conditions. [•] The stabilization of meta-stable orthorhombic SrIrO3 was quantitatively understood by lattice mismatch strain. [ABSTRACT FROM AUTHOR]

The initial growth modes of Bi4LaTi3FeO15 thin films on (001) SrTiO3, (001) MgO and (001) Y:ZrO2 (YSZ) substrates are studied. Detailed crystal structure, microstructure and surface morphology characterizations substantiate that Bi4LaTi3FeO15 films grow on these substrates via three-dimensional grain growth mode. The synthesized Bi4LaTi3FeO15 films on (001) MgO and (001) SrTiO3 substrates do have c-axis epitaxial Aurivillius layered structure, and have relative smooth surface roughness. While films grown on (001) YSZ show the polycrystalline quality with large surface roughness. The different crystal quality of films grown on MgO/SrTiO3 and YSZ substrates is explained qualitatively by considering the different atomic surface structures of these substrates. [ABSTRACT FROM AUTHOR]

Abstract: La-substituted BiFeO3, Bi0.8La0.2FeO3, thin films were fabricated on Pt/Ti/SiO2/Si substrates by pulsed laser deposition. X-ray diffraction and high-resolution transmission electron microscope were used to analyze the structures of the films. The results show the films fabricated under optimized growth condition are (012) textured. X-ray photoemission spectroscopy results indicate that the oxidation state of Fe ion is Fe3+ in the films without detectable Fe2+. The films show low leakage current and excellent dielectric characters. Multiferroic properties with a remnant ferroelectric polarization of 5.2μC/cm2 and a remanent magnetization of 0.02μB/Fe were established. These results have some implications for further research. [Copyright &y& Elsevier]

Abstract: 1–3 and 2–2 types Pb(Zr0.53Ti0.47)O3–CoFe2O4 (PZT–CFO) composite films with controllable microstructures, consisted by CFO nanopillar embedded in PZT matrix and PZT–CFO gratings respectively, have been fabricated on Pt/Ti/SiO2/Si substrates by combining lithography technology and pulsed laser deposition. X-ray diffraction confirms that the films are well crystallized under optimized postannealing conditions. Scanning electron microscope reveals that the periodic microstructures can be well controlled. Especially, intrinsic room temperature ferroelectric and ferrimagnetic behaviors are observed simultaneously. The structure–properties relationship is discussed. Our results may provide an alternative method to design and prepare multiferroic composite films with controllable microstructures. [ABSTRACT FROM AUTHOR]