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Experimental measurements clearly reveal the presence of bulk superconductivity in the CsPb x Bi 4− x Te 6 (0.3≤ x ≤1.0) materials, i.e. the first member of the thermoelectric series of Cs[Pb m Bi 3 Te 5+ m ], these materials have the layered orthorhombic structure containing infinite anionic [PbBi 3 Te 6 ] − slabs separated with Cs + cations. Temperature dependences of electrical resistivity, magnetic susceptibility, and specific heat have consistently demonstrated that the superconducting transition in Cs 0.96 Pb 0.25 Bi 3.75 Te 6.04 occurs at T c =3.1 K, with a superconducting volume fraction close to 100% at 1.8 K. Structural study using aberration-corrected STEM/TEM reveals a rich variety of microstructural phenomena in correlation with the Pb-ordering and chemical inhomogeneity. The superconducting material Cs 0.96 Pb 0.25 Bi 3.75 Te 6.04 with the highest T c shows a clear ordered structure with a modulation wave vector of q ≈ a */2+ c */1.35 on the a – c plane. Our study evidently demonstrates that superconductivity deriving upon doping of narrow-gap semiconductor is a viable approach for exploration of novel superconductors. [ABSTRACT FROM AUTHOR]

Abstract: When seeking a solution in series form, the number of terms needed to satisfy some preset requirements is unknown in the beginning. An iterative formulation is proposed so that when an approximation is available, the number of effective terms can be doubled in one iteration by solving a set of linear equations. This is a new extension of the Newton iteration in solving nonlinear algebraic equations to solving nonlinear differential equations by series. When Fourier series is employed, the method is called the residue harmonic balance. In this paper, the fractional order van der Pol oscillator with fractional restoring and damping forces is considered. The residue harmonic balance method is used for generating the higher-order approximations to the angular frequency and the period solutions of above mentioned fractional oscillator. The highly accurate solutions to angular frequency and limit cycle of the fractional order van der Pol equations are obtained analytically. The results that are obtained reveal that the proposed method is very effective for obtaining asymptotic solutions of autonomous nonlinear oscillation systems containing fractional derivatives. The influence of the fractional order on the geometry of the limit cycle is investigated for the first time. [Copyright &y& Elsevier]

Abstract: The structural features of the “5M” martensitic phase in Ni2FeGa alloys have been determined by electron diffraction using the multi-slice least-squares (MSLS) method. The results demonstrate that the “5M” phase contains an evident cooperative effect of monoclinic distortion and sinusoidal modulation along the [110] c direction. Theoretical simulations based on our refined data suggest that the “5M” martensitic phase observed in Ni–Fe–Ga and Ni–Mn–Ga has visible common behaviors in both stacking sequence and local structural distortion. Considering the cooperative effect of monoclinic distortion and sinusoidal modulation, we demonstrate that the “7M” martensitic phase could adopt two equivalent structural phases corresponding with the stacking sequences of and , respectively. [Copyright &y& Elsevier]

Abstract: Transmission electron microscopy (TEM) investigations on Nd2/3− x Li3 x TiO3 with x=0.14 reveal a rich variety of structural features in the samples prepared under different conditions, such as superstructures, anti-phase domains, and nano-chessboard structures. Our careful analysis shows that these structural phenomena can be fundamentally understood as the combination of structural effects of (Nd, Li)-ordering along the 〈001〉p direction and the spinodal decomposition along the 〈100〉p/〈010〉p direction. The coexistence of phase separation and cation ordering can lead to visible nano-structural complexities in many crystals, as the typical results, the regular lamella structure, nano-chessboard structures and anti-phase boundaries have been extensively studied. [Copyright &y& Elsevier]