Transverse electron transport in magnetic materials - manifested in effects such as the anomalous Hall and Nernst effects - holds promise for spintronic and thermoelectric applications. While recent advances have focused on enhancing such transport through topological single crystals via intrinsic mechanisms linked to Berry curvature, practical limitations remain due to their mechanical fragility and narrow material scope. Here, we demonstrate a distinct approach for transverse transport enhancement based on composite formation. Using both theoretical modeling and experiments, we show that disordered mixtures of two ferromagnetic materials can exhibit significantly stronger transverse electron deflection than either constituent alone. This enhancement originates from meandering electron pathways created by the disordered mixture of two materials and does not rely on long-range crystalline order. The identified requirements for this mechanism can be broadly satisfied across different material systems, offering a universal and tunable strategy to engineer large transverse responses in structurally robust platforms.
A variety of performance demands are being placed on material systems, including desirable mechanical, thermal, electrical, optical, acoustic and flow properties. The purpose of the present article is to review the emerging field of disordered hyperuniform composites and their novel multifunctional characteristics. Disordered hyperuniform media are exotic amorphous states of matter that are characterized by an anomalous suppression of large-scale volume-fraction fluctuations compared to those in "garden-variety" disordered materials. Such unusual composites can have advantages over their perio…
Thin shell carbon fiber composites have great potential for structures that require large recoverable deformations, high stiffness and low weight, as in deployable space structures, biomedical devices and robotics. Despite being astonishingly flexible in fiber direction, thin shells are highly sensitive to off-axis loading. High sensitivity to imperfections, manufacturing limitations and a missing in-depth mechanical understanding hinders the creation of transversely robust shells. This paper provides crucial insights into the factors influencing the transverse strength of ultra-thin composite…
The use of composite materials for structures subjected to impacts requires a deep understanding about the dynamic behaviour of the material. To this end, a physically-based computational micromechanics simulation tool has been developed to predict failure initiation in a composite ply over a wide range of strain rates. The computational micromechanics framework incorporates constitutive models for the fibre, matrix and fibre-matrix interface, which are partly calibrated with novel micromechanical testing techniques. The simulation tool was applied to two matrix-dominated deformation modes of …
Generalized two-body self-consistent theory of random linear dielectric composites: an effective-medium approach to clustering in highly-disordered media
Theoretical Prediction of the Effective Dynamic Dielectric Constant of Disordered Hyperuniform Anisotropic Composites Beyond the Long-Wavelength Regime
We derive exact nonlocal expressions for the effective dielectric constant tensor ${\boldsymbol \varepsilon}_e({\bf k}_I, ω)$ of disordered two-phase composites and metamaterials from first principles. This formalism extends the long-wavelength limitations of conventional homogenization estimates of ${\boldsymbol \varepsilon}_e({\bf k}_I, ω)$ for arbitrary microstructures so that it can capture spatial dispersion well beyond the quasistatic regime (where $ω$ and ${\bf k}_I$ are frequency and wavevector of the incident radiation). This is done by deriving nonlocal strong-contrast expansions tha…
Composites are ideally suited to achieve desirable multifunctional effective properties since the best properties of different materials can be judiciously combined with designed microstructures. Here we establish cross-property relations for two-phase composite media that link effective elastic and electromagnetic wave characteristics to one another, including the respective effective wave speeds and attenuation coefficients, which facilitate multifunctional material design. This is achieved by deriving accurate formulas for the effective electromagnetic and elastodynamic properties that depe…
While classical percolation is well understood, percolation effects in randomly packed or jammed structures are much less explored. Here we investigate both experimentally and theoretically the electrical percolation in a binary composite system of disordered spherocylinders, to identify the relation between structural (percolation) and functional properties of nanocomposites. Experimentally, we determine the percolation threshold $p_c$ and the conductivity critical exponent $t$ for composites of conducting (CrO$_2$) and insulating (Cr$_2$O$_3$) rodlike nanoparticles that are nominally geometr…
Phase Transition of the Uniaxial Disordered Ferroelectric Sr$_{0.61}$Ba$_{0.39}$Nb$_2$O$_6$
用中子散射方法研究了Sr $_{0.61}$ Ba $_{0.39}$ Nb $_2$ O $_6$（SBN-61）的铁电相变.铁电极化是沿着晶体学$c$ -轴，但是沿着$<$ 1，1，0 $>$方向传播的横向声学分支没有显示出与该转变相关的任何异常。我们没有发现软横光学声子的证据。然而，我们确实观察到弹性漫散射。这种散射的强度随着样品从远高于相变的温度冷却而增加。与这种漫散射相关的磁化率遵循SBN-61的介电常数的异常。低于T $_\mathrm{c}$，这种散射的形状与铁电畴壁的预期散射一致。我们的研究结果表明，尽管明显的化学无序SBN-61的行为作为一个经典的有序-无序单轴铁电体的临界波动范围$<10^{-11}$ s。
