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Single crystals of the quaternary R‐type ferrites BaLiRu5O11 [a = 11.628(6) Å, c = 13.7596(5) Å], and BaCu1+xRu5–xO11 [a = 11.6825(6) Å, c = 13.8051(7) Å], and their quinary solid solution BaLi1–xCux+δRu5–δO11 [a = 11.6453(2) Å, c = 13.7772(3) Å] were obtained by flux growth technique. X‐ray diffraction reveals the compounds to crystallize in space group P63/m with Z = 8. Measurements of the magnetic susceptibility of BaLiRu5O11 and BaCu1+xRu5–xO11, applying Curie–Weiss fits, confirm their paramagnetic behavior with temperature independent contributions of χ0,mol = 3.27 × 10–3 cm3·mol–1 and χ0,mol = 2.47 × 10–3 cm3·mol–1, respectively. Furthermore, the valence state of Ru in BaLiRu5O11 and BaCu1+xRu5–xO11 was determined to +3.8 by X‐ray absorption spectroscopy. Cu in BaCu1+xRu5–xO11 is dominating in a +2 state according to X‐ray photoelectron and X‐ray absorption spectroscopy, while a minor amount in +1 state may represent the excess copper substituting some Ru within a distorted Kagome net arrangement. [ABSTRACT FROM AUTHOR]

We present a combined experimental and theoretical Pb‐L3 X‐ray absorption near‐edge spectroscopy (XANES) to investigate the chemical state of Pb in transition metal perovskites PbTMO3 (TM = Ti, Ni). A pre‐edge feature originated from the excitation of a 2p core electron to the 6s orbital is only observed in PbNiO3, from which the valence of Pb is determined to be Pb4+ with two 6s holes. However, no such 2p–6s related excitation was observed in PbTiO3, indicating the formation of Pb2+ with fully occupied 6s2 state in this materials. Our results demonstrate that this pre‐edge peak from dipole allowed 2p–6s transition is a sensitive finger‐print of the Pb valence state in solid state materials. [ABSTRACT FROM AUTHOR]

Self-assembled vertical heterostructure with a high interface-to-volume ratio offers tremendous opportunities to realize intriguing properties and advanced modulation of functionalities. Here, a heterostructure composed of two visible-light photocatalysts, BiFeO3 (BFO) and ε-Fe2O3 ( ε-FO), is designed to investigate its photoelectrochemical performance. The structural characterization of the BFO-FO heterostructures confirms the phase separation with BFO nanopillars embedded in the ε-FO matrix. The investigation of band structure of the heterojunction suggests the assistance of photoexcited carrier separation, leading to an enhanced photoelectrochemical performance. The insights into the charge separation are further revealed by means of ultrafast dynamics and electrochemical impedance spectroscopies. This work shows a delicate design of the self-assembled vertical heteroepitaxy by taking advantage of the intimate contact between two phases that can lead to a tunable charge interaction, providing a new configuration for the optimization of photoelectrochemical cell. [ABSTRACT FROM AUTHOR]

A chemically induced magnetoelectric coupling effect in ferroelectric/antiferromagnetic self-assembled vertical nanocomposites is designed. A concrete connection between chemical diffusion and the induced magnetic moment is revealed. Importantly, this study shows the strong magnetoelectric coupling effect, which is key to extend the design of functionality in vertical nanocomposites. [ABSTRACT FROM AUTHOR]

We grow perpendicular L10-FePt films epitaxially on (001)[Pb(Mg1/3Nb2/3)]0.7-(PbTiO3)0.3 ferroelectric substrates. Due to the magnetostriction effect, the out-of-plane coercivity (Hc⊥) of the L10-FePt varies with applied electric fields, showing an asymmetric butterfly-like loop. The Hc⊥ at the zero-electric-field state (Hc⊥,0) shows a nonvolatile change, depending on the direction of the poling electric field. The magnitude of nonvolatile magnetic anisotropy change, induced by the ferroelectric field effect, can be comparable to the anisotropy change induced by pure electric fields. The nonvolatile magnetic anisotropy change is inversely proportional to the FePt thickness and can be eliminated by inserting a metallic intermediate layer. [ABSTRACT FROM AUTHOR]

Li-Ti Cation Mixing Enhanced Structural and Performance Stability of Li-Rich Layered Oxide The affiliation information for the National Synchrotron Radiation Research Center was presented incorrectly. The authors apologize for any inconvenience caused. [Extracted from the article]

Li‐rich layered metal oxides are one type of the most promising cathode materials in lithium‐ion batteries but suffer from severe voltage decay during cycling because of the continuous transition metal (TM) migration into the Li layers. A Li‐rich layered metal oxide Li1.2Ti0.26Ni0.18Co0.18Mn0.18O2 (LTR) is hereby designed, in which some of the Ti4+ cations are intrinsically present in the Li layers. The native Li–Ti cation mixing structure enhances the tolerance for structural distortion and inhibits the migration of the TM ions in the TMO2 slabs during (de)lithiation. Consequently, LTR exhibits a remarkable cycling stability of 97% capacity retention after 182 cycles, and the average discharge potential drops only 90 mV in 100 cycles. In‐depth studies by electron energy loss spectroscopy and aberration‐corrected scanning transmission electron microscopy demonstrate the Li–Ti mixing structure. The charge compensation mechanism is uncovered with X‐ray absorption spectroscopy and explained with the density function theory calculations. These results show the superiority of introducing transition metal ions into the Li layers in reinforcing the structural stability of the Li‐rich layered metal oxides. These findings shed light on a possible path to the development of Li‐rich materials with better potential retention and a longer lifespan. [ABSTRACT FROM AUTHOR]

In the past decades, mesocrystal, a kind of nanocrystals with specific crystallographic orientation, has drawn a lot of attention due to its intriguing functionalities. While the research community keeps searching for new mesocrystal systems, it is equally crucial to develop new approaches to tune the properties of mesocrystals. In this work, a self-organized two-dimensional mesocrystal composed of highly oriented CoFe2O4 (CFO) nano-crystals with assistance of different perovskite matrices is studied as a model system. We have demonstrated that the strain state and corresponding magnetic properties of the CFO mesocrystal can be modulated by changing the surrounding perovskite matrix through their intimate structural coupling. Interestingly, this controllability is more strongly correlated to the competition of bonding strength between the matrices and the CFO mesocrystals rather than the lattice mismatch. When embedded in a matrix with a higher melting point or stiffness, the CFO mesocrystal experiences higher out-of-plane compressive strain and shows a stronger magnetic anisotropy as well as cation site-exchange. Our study suggests a new pathway to tailor the functionalities of mesocrystals. [ABSTRACT FROM AUTHOR]

Spin state transitions and intermetallic charge transfers can essentially change material structural and physical properties while excluding external chemical doping. However, these two effects have rarely been found to occur sequentially in a specific material. In this article, we show the realization of these two phenomena in a perovskite oxide PbCoO 3 with a simple ABO 3 composition under high pressure. PbCoO 3 possesses a peculiar A- and B-site ordered charge distribution Pb 2+ Pb 4+ 3 Co 2+ 2 Co 3+ 2 O 12 with insulating behavior at ambient conditions. The high spin Co 2+ gradually changes to low spin with increasing pressure up to about 15 GPa, leading to an anomalous increase of resistance magnitude. Between 15 and 30 GPa, the intermetallic charge transfer occurs between Pb 4+ and Co 2+ cations. The accumulated charge-transfer effect triggers a metal-insulator transition as well as a first-order structural phase transition toward a Tetra.-I phase at the onset of ∼20 GPa near room temperature. On further compression over 30 GPa, the charge transfer completes, giving rise to another first-order structural transformation toward a Tetra.-II phase and the reentrant electrical insulating behavior.

Magnetic and multiferroic nanocomposites with two distinct phases have been a topic of intense research for their profound potential applications in the field of spintronics. In addition to growing high-quality phase separated heteroepitaxial nanocomposites, the strain engineering that is conducive to enhance the tunability of material properties, in general, and the magnetic properties, in particular, is of utmost importance in exploring new possibilities. Here, we investigated the magneto-structural coupling between antiferromagnetic BiFeO3 (BFO) and ferrimagnetic CoFe2O4 (CFO) in self-assembled vertically aligned nanocomposites grown on LaAlO3 (LAO) and SrTiO3 (STO) substrates. We found that BFO exhibits tetragonal (T) and rhombohedral (R) structures as the stable phases and CFO has high magnetocrystalline anisotropy even in the form of nanocomposites. The temperature and magnetic field dependent magnetizations of T_BFO-CFO/LAO and R_BFO-CFO/STO nanocomposites primarily demonstrate the magnetoelastic coupling between these variants.

Background: To explore whether combining inhibitors that target the insulin-like growth factor receptor (IGFR)/PI3K/Akt/mTOR signaling pathway (vertical blockade) can improve treatment efficacy for hepatocellular carcinoma (HCC)., Methods: HCC cell lines (including Hep3B, Huh7, and PLC5) and HUVECs (human umbilical venous endothelial cells) were tested. The molecular targeting therapy agents tested included NVP-AEW541 (IGFR kinase inhibitor), MK2206 (Akt inhibitor), BEZ235 (PI3K/mTOR inhibitor), and RAD001 (mTOR inhibitor). Potential synergistic antitumor effects were tested by median dose-effect analysis in vitro and by xenograft HCC models. Apoptosis was analyzed by flow cytometry (sub-G1 fraction analysis) and Western blotting. The activities of pertinent signaling pathways and expression of apoptosis-related proteins were measured by Western blotting., Results: Vertical blockade induced a more sustained inhibition of PI3K/Akt/mTOR signaling activities in all the HCC cells and HUVEC tested. Synergistic apoptosis-inducing effects, however, varied among different cell lines and drug combinations and were most prominent when NVP-AEW541 was combined with MK2206. Using an apoptosis array, we identified survivin as a potential downstream mediator. Over-expression of survivin in HCC cells abolished the anti-tumor synergy between NVP-AEW541 and MK2206, whereas knockdown of survivin improved the anti-tumor effects of all drug combinations tested. In vivo by xenograft studies confirmed the anti-tumor synergy between NVP-AEW541 and MK2206 and exhibited acceptable toxicity profiles., Conclusions: Vertical blockade of the IGFR/PI3K/Akt/mTOR pathway has promising anti-tumor activity for HCC. Survivin expression may serve as a biomarker to predict treatment efficacy.

Complex oxide nanocrystals with a spinel structure show their remarkable optical, electronic, mechanical, thermal, and magnetic properties. In this study, we present a simple yet versatile strategy to grow self-assembled epitaxial CoFe2O4 nanocrystals with well-controlled size (less than 10 nm) and single orientation. CoFe2O4 nanocrystals were fabricated via phase separation in a BiFeO3-CoF2O4 ultrathin film by pulsed laser deposition. The coherent strain at the BiFeO3-CoF2O4 interface suppressed the growth of the nanocrystals regardless of substrate temperatures. This strain also resulted in the ferromagnetic anisotropy and interesting conducting behaviors of ultrafine CFO nanocrystals.

In this study, advanced control of crystallographic orientations and magnetic properties of self-assembled nanostructures via rational selections of substrates is demonstrated. We show that in the perovskite-spinel BiFeO(3)-CoFe(2)O(4) model system the crystal orientation of self-assembled CoFe(2)O(4) nanopillars can be tuned among (001), (011), and (111), while that of the BiFeO(3) matrix is fixed in (001). Moreover, the resultant CoFe(2)O(4) nanopillars appear in various shapes: pyramid, roof, and triangular platform, respectively. The tunable nanostructures through this approach enable the control of material functionality such as the magnetic anisotropy of CoFe(2)O(4). This study opens a new pathway for the engineering of self-assembled heteroepitaxial nanostructures.