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Magnetorheological (MR) fluids are magnetic responsive smart materials that are widely used in real‐time damping adjustment devices. However, a major challenge for MR fluids is balancing the constraints relationship among various key performances. This study demonstrates that by utilizing home‐made high saturation magnetization (208.0 emu g−1) nanoparticles as the second component in the preparation of cross‐scale bidisperse MR fluids, the shortcomings of monodisperse micron particles performance can be compensated, effectively balancing the relationship between various performances. This is attributed to the fact that the addition of nanoparticles enhances the density of chain structures under an applied magnetic field, while reducing the overall particle density without a magnetic field. By replacing part of micron particles with nanoparticles, the phenomenon of significant increase in zero‐field viscosity caused by the direct introduction of nanoparticles is avoided. The optimal content of nanoparticles in MR fluids is preliminarily explored, and the results indicate that Micro‐Nano bidisperse MR fluids exhibit a high dynamic yield strength (58.3 kPa when 436 kA m−1), excellent sedimentation stability (82.6% when 7 days), suitable zero‐field viscosity (1.25 Pa s when 100 s−1), and ideal reversibility. Most importantly, the simple preparation method adds significant engineering application value to these MR fluids. [ABSTRACT FROM AUTHOR]

BaTiO3 heated in an excess of SrCl2 at 1150 °C converts to SrTiO3 through an ion exchange reaction. The SrTiO3 synthesized by ion exchange produces hydrogen from pH 7 water at a rate more than twice that of conventional SrTiO3 treated identically. The apparent quantum yield for hydrogen production in pure water of the ion exchanged SrTiO3 is 11.4% under 380 nm illumination. The catalyst resulting from ion‐exchange differs from conventional SrTiO3 by having ≈2% residual Ba, inhomogeneous Cl‐doping at a concentration less than 1%, Kirkendall voids in the centers of particles that result from the unequal rates of Sr and Ba diffusion together with the transport of Ti and O, and nanoscale regions near the surface that have lattice spacings consistent with the Sr‐excess phase Sr2TiO4. The increased photochemical efficiency of this nonequilibrium structure is most likely related to the Sr‐excess, which is known to compensate donor defects that can act as charge traps and recombination centers. [ABSTRACT FROM AUTHOR]

A systematic investigation has been performed to optimize the microstructure of L10-FePt–SiOx granular thin films as recording media for heat-assisted magnetic recording. The FePt–boron nitride (BN) nucleation layer, which is stable even at 700 °C, is used to control the grain sizes and microstructure during the high-temperature processing. The study finds that films of high-aspect-ratio FePt grains with well-formed silicon oxide (SiOx) grain boundaries require the grading of the deposition temperature during film growth as well as the grading of the silicon oxide concentration. Well-isolated columnar grains of L10-FePt with an average height greater than 11 nm and diameters less than 7 nm have been achieved. Transmission electron microscopy analysis of the microstructures of samples produced under a variety of non-optimal conditions is presented to show how the microstructure of the films depends on each of the sputtering parameters. [ABSTRACT FROM AUTHOR]