Read by QxMD icon Read


Pegah Mirzadeh Vaghefi, Ali Baghizadeh, Armando A C S Lourenço, Vitor S Amaral, Andre L Kholkin
We report an effect of giant surface modification of a 5.6 nm thick BaTiO₃ film grown on Si (100) substrate under poling by conductive tip of a scanning probe microscope (SPM). The surface can be locally elevated by about 9 nm under -20 V applied during scanning, resulting in the maximum strain of 160%. The threshold voltage for the surface modification is about 12 V. The modified topography is stable enough with time and slowly decays after poling with the rate ~0.02 nm/min. Strong vertical piezoresponse after poling is observed, too...
September 20, 2017: Materials
Menghao Wu, Xiao Cheng Zeng
Atomically thin Bi2O2Se has been recently synthesized and it possesses ultra-high mobility (Nat Nanotech. 2017, 12, 530; Nano Lett. 2017, 17, 3021). Herein, we show first-principles evidence that Bi2O2Se and a related class of bismuth oxychalcogenides, such as Bi2O2S and Bi2O2Te, not only are novel semiconductors with ultra-high mobility but also possesses previously unreported ferroelectricity/ferroelasticity. Such a unique combination of semiconducting with ferroelectric/ferroelastic properties enables bismuth oxychalcogenides to potentially meet a great challenge, that is, integration of room-temperature functional non-volatile memories into future nanocircuits...
September 20, 2017: Nano Letters
Jing Shi, Rongfeng Zhu, Xing Liu, Bijun Fang, Ningyi Yuan, Jianning Ding, Haosu Luo
The 1 wt % Li-doped (Ba0.85Ca0.15)(Zr0.1Ti0.9)O₃ (BCZT-Li) ceramics prepared by the citrate method exhibit improved phase purity, densification and electrical properties, which provide prospective possibility to develop high-performance electrocaloric materials. The electrocaloric effect was evaluated by phenomenological method, and the BCZT-Li ceramics present large electrocaloric temperature change ∆T, especially large electrocaloric responsibility ξ = ∆Tmax/∆Emax, which can be comparable to the largest values reported in the lead-free piezoelectric ceramics...
September 18, 2017: Materials
Yajun Zhang, Jie Wang, M P K Sahoo, Takahiro Shimada, Takayuki Kitamura
Perovskite stannates such as BaSnO3 and SrSnO3 exhibit promising photovoltaic properties, and hold promise for application in solar cell devices. However, the lack of ferroelectricity and the wide band gap in these materials limit their potential for photovoltaic applications. Here, by first-principles calculations, we demonstrate the realization of a primary ferroelectric polarization in non-ferroelectric BaSnO3 and SrSnO3 through strain engineering. In addition to the appearance of polarization, the band gaps of the materials are greatly narrowed when the paraelectric to ferroelectric phase transition takes place under compressive strain...
September 19, 2017: Physical Chemistry Chemical Physics: PCCP
Mandar M Shirolkar, Jieni Li, Xiaolei Dong, Ming Li, Haiqian Wang
In recent years, BiFeO3 has attracted significant attention as an interesting multiferroic material in the exploration of fundamental science and development of novel applications. Our previous study (Phys. Chem. Chem. Phys.18, 2016, 25409) highlighted the interesting physicochemical features of BiFeO3 of sub-5 nm dimension. The study also accentuated the existence of weak ferroelectricity at sub-5 nm dimensions in BiFeO3. Based on this feature, we have prepared thin films using sub-5 nm BiFeO3 nanoparticles and explored various physicochemical properties of the thin film...
September 19, 2017: Physical Chemistry Chemical Physics: PCCP
Emerson Coy, Piotr Graczyk, Luis Yate, Karol Załęski, Jacek Gapiński, Piotr Kuświk, Sławomir Mielcarek, Feliks Stobiecki, Bogusław Mróz, Cesar Ferrater, Stefan Jurga
Gd2(MoO4)3 (GMO) is a well-studied multiferroic material that exhibits full ferroelectric and ferroelastic behavior at room temperature. However, its difficult stabilization in thin films has prevented the study and exploitation of its multiferroic properties in different architectures. Here, we report on the study of GMO thin films deposited on Si(001) substrates by Pulsed Laser Deposition (PLD). The physicochemical properties of the films are discussed and studied. Results obtained by X-ray diffraction, X-ray photoelectron spectroscopy, high resolution transmission microscopy and second harmonic generation show that the orthorhombic (β'-GMO) multiferroic phase can be stabilized and homogenized by post deposition thermal reconstruction...
September 18, 2017: Scientific Reports
Guangliang Hu, Gaind P Pandey, Qingfeng Liu, Radhika S Anaredy, Chunrui Ma, Ming Liu, Jun Li, Scott K Shaw, Judy Z Wu
Electrochemical effects manifest as nonlinear responses to an applied electric field in electrochemical devices, and are linked intimately to the molecular orientation of ions in the electric double layer (EDL). Herein, we probe the origin of the electrochemical effect using a double-gate graphene field effect transistor (GFET) of ionic liquid N,N-diethyl-N-(2-methoxyethyl)-N-methylammonium bis-(trifluoromethylsulfonyl)-imide (DEME-TFSI) top-gate, paired with a ferroelectric Pb0.92La0.08Zr0.52Ti0.48O3 (PLZT) back-gate of compatible gating efficiency...
September 18, 2017: ACS Applied Materials & Interfaces
M Aftabuzzaman, M A Helal, R Paszkowski, J Dec, W Kleemann, S Kojima
Static and dynamic heterogeneity of disordered system is one of the current topics in materials science. In disordered ferroelectric materials with random fields, dynamic polar nanoregions (PNRs) appear at Burns temperature and freeze into nanodomain state below Curie temperature (T C). This state is very sensitive to external electric field and aging by which it gradually switches into macrodomain state. However, the role of PNRs in such states below T C is still a puzzling issue of materials science. Electric field and aging effects of uniaxial ferroelectric Sr x Ba1-x Nb2O6 (x = 0...
September 14, 2017: Scientific Reports
Hailing Sun, Xiao Wu, Deng Feng Peng, K W Kwok
Ferroelectric oxides with luminescent ions hold great promise in future optoelectronic devices because of their unique photoluminescence and inherent ferroelectric properties. Intriguingly, the photoluminescence performance of ferroelectric ceramics could be modulated by an external electric field. However, researchers face a current challenge of the diminutive extent and degree of reversibility of the field-driven modification that hinder their use in room-temperature practical applications. Within the scope of current contribution in rare-earth-doped bismuth sodium titanate relaxors, the most important information to be noted is the shifting of the depolarization temperature toward room temperature and the resulting considerable enhancement in ergodicity, as evidenced by the dielectric properties, polarization, and strain hysteresis, as well as the in situ Raman/X-ray diffraction studies...
September 21, 2017: ACS Applied Materials & Interfaces
Zongfan Duan, Ying Cui, Gaoyang Zhao, Xiaoguang Li, Biaolin Peng, Chunchun Han
A La0.67Sr0.33MnO3 (LSMO) ferromagnetic layer and a Nd(3+)/Hf(4+) co-substituted Bi4Ti3O12 (Bi3.15Nd0.85Ti3-xHfxO12 (BNTHx, x = 0, 0.025, 0.05, 0.1 and 0.15)) ferroelectric layer were successively deposited onto the (00 l)-oriented LaNiO3 (LNO) layer buffered (001) Si substrate via all chemical solution deposition (CSD) method. As a result, the BNTHx/LSMO ferromagnetic-ferroelectric composite films integrated on Si substrate exhibit high c-axis orientation. The Nd(3+)/Hf(4+) co-substituted BNTHx films have the lower leakage current and the better ferroelectric properties than the mono-substituted Bi4Ti3O12 (Bi3...
September 12, 2017: Scientific Reports
Kun Zhai, Yan Wu, Shipeng Shen, Wei Tian, Huibo Cao, Yisheng Chai, Bryan C Chakoumakos, Dashan Shang, Liqin Yan, Fangwei Wang, Young Sun
Multiferroics materials, which exhibit coupled magnetic and ferroelectric properties, have attracted tremendous research interest because of their potential in constructing next-generation multifunctional devices. The application of single-phase multiferroics is currently limited by their usually small magnetoelectric effects. Here, we report the realization of giant magnetoelectric effects in a Y-type hexaferrite Ba0.4Sr1.6Mg2Fe12O22 single crystal, which exhibits record-breaking direct and converse magnetoelectric coefficients and a large electric-field-reversed magnetization...
September 12, 2017: Nature Communications
Hongwei Huang, Shuchen Tu, Xin Du, Yihe Zhang
Introducing a polarization electric field in photocatalyst system is regarded asa new concept for photocatalytic activity enhancement. In this work, we first unearth that the spontaneous polarization of ferroelectric BaTiO3 promotes the photocatalytic and molecular oxygen activation performance of the narrow-band-gap semiconductor BiOI. Ferroelectric tetragonal-phase BaTiO3 (T-BaTiO3) were prepared via calcination of nonferroelectric cubic-phase BaTiO3 (C-BaTiO3), and their polarization ability was verified via ultrasonication-assisted piezoelectric catalytic degradation...
September 6, 2017: Journal of Colloid and Interface Science
Hyeon Han, Ji Hyun Lee, Hyun Myung Jang
The synthesis of high-purity BiFeO3 (BFO) ceramic by solid-state reaction is known to be very difficult due to inevitable formation of the secondary phases, mostly mullite-type Bi2Fe4O9 and sillenite-type Bi25FeO39. In particular, it is very difficult to completely remove the Bi-deficient Bi2Fe4O9 phase from sintered ceramic BFO targets. This problem consequently leads to the difficulty of fabricating high-quality BFO thin films using these sintered targets. Herein, we introduce a simple but effective low-temperature processing scheme for removing impurity phases in which optimized processing conditions are obtained by chemically correlating the first calcination step with the subsequent leaching and sintering steps...
September 12, 2017: Inorganic Chemistry
Suman Raj Panday, Benjamin M Fregoso
The two-dimensional ferroelectrics GeS, GeSe, SnS and SnSe are expected to have large spontaneous in-plane electric polarization and enhanced shift-current response. Using density functional methods, we show that these materials also exhibit the largest effective second harmonic generation reported so far. It can reach magnitudes up to 10 nm/V which is about an order of magnitude larger than that of prototypical GaAs. To rationalize this result we model the optical response with a simple one-dimensional two-band model along the spontaneous polarization direction...
September 12, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Aleksander Matavž, Vid Bobnar, Barbara Malic
The surface properties of a substrate are among the most important parameters in the printing technology of functional materials, determining not only the printing resolution but also the stability of the printed features. This paper addresses the wetting difficulties encountered during inkjet printing on homogeneous substrates as a result of improper surface properties. We show that the wetting of a substrate and, consequently, the quality of the printed pattern, can be mediated through the deposition of polymeric layers that are a few nanometers thick...
September 12, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Yuping Shi, Limin Huang, Ai Kah Soh, George J Weng, Shuangyi Liu, Simon A T Redfern
Electrocaloric (EC) materials show promise in eco-friendly solid-state refrigeration and integrable on-chip thermal management. While direct measurement of EC thin-films still remains challenging, a generic theoretical framework for quantifying the cooling properties of rich EC materials including normal-, relaxor-, organic- and anti-ferroelectrics is imperative for exploiting new flexible and room-temperature cooling alternatives. Here, we present a versatile theory that combines Master equation with Maxwell relations and analytically relates the macroscopic cooling responses in EC materials with the intrinsic diffuseness of phase transitions and correlation characteristics...
September 11, 2017: Scientific Reports
Asad Muhammad Iqbal, Ghulam Hassnain Jaffari, Mohson Saleemi, Abdullah Ceylan
We presented detailed frequency and temperature dependent dielectric response in Eu1-xBaxTiO3 (0 < x < 0.5). Excluding grain boundary effects, four relaxation mechanisms have been observed. Relaxation dynamics were observed to arise due to hopping conduction associated with defects namely, oxygen vacancies, Eu3+ and Ti3+ ions. Dielectric relaxation analysis led to identification of Ti ions in two different environments with different relaxation rates in the overall EuTiO3 perovskite structure. Emergence of another relaxation mechanism associated with ferroelectric order as a consequence of formation of polar regions have also been observed for higher Ba concentrations...
September 11, 2017: Journal of Physics. Condensed Matter: An Institute of Physics Journal
Gaoyang Gou, Nenian Charles, Jing Shi, James M Rondinelli
The double perovskite CaMnTi2O6, is a rare A-site ordered perovskite oxide that exhibits a sizable ferroelectric polarization and relatively high Curie temperature. Using first-principles calculations combined with detailed symmetry analyses, we identify the origin of the ferroelectricity in CaMnTi2O6. We further explore the material properties of CaMnTi2O6, including its ferroelectric polarization, dielectric and piezoelectric responses, magnetic order, electronic structure, and optical absorption coefficient...
September 11, 2017: Inorganic Chemistry
Yi-Guang Wang, Xin-Gui Tang, Qiu-Xiang Liu, Yan-Ping Jiang, Li-Li Jiang
Sr(Ti1-xFex)O3-δ (0 ≤ x ≤ 0.2) thin films were grown on Si(100) substrates with LaNiO₃ buffer-layer by a sol-gel process. Influence of Fe substitution concentration on the structural, ferroelectric, and magnetic properties, as well as the leakage current behaviors of the Sr(Ti1-xFex)O3-δ thin films, were investigated by using the X-ray diffractometer (XRD), atomic force microscopy (AFM), the ferroelectric test system, and the vibrating sample magnetometer (VSM). After substituting a small amount of Ti ion with Fe, highly enhanced ferroelectric properties were obtained successfully in SrTi0...
September 8, 2017: Nanomaterials
Verónica Jornet-Mollá, Yan Duan, Carlos Giménez-Saiz, Yuan-Yuan Tang, Peng-Fei Li, Francisco M Romero, Ren-Gen Xiong
A dual-function material in which ferroelectricity and spin crossover coexist in the same temperature range has been obtained. Our synthetic strategy allows the construction of acentric crystal structures in a predictable way and is based on the high directionality of hydrogen bonds. The well-known iron(II) spin crossover complex [Fe(bpp)₂]²+ (bpp = 2,6-bis(pyrazol-3-yl)pyridine), a four-fold noncentrosymmetric H-bond donor, was combined with a disymmetric H-bond acceptor such as the isonicotinate (isonic) anion to afford [Fe(bpp)₂](isonic)₂·2H₂O...
September 7, 2017: Angewandte Chemie
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"