RESUMEN
A bimorph composed of ferrimagnetic cobalt ferrite (CoFe2O4, CFO) and flexible muscovite was fabricated via van der Waals epitaxy. The combination of X-ray diffraction and transmission electron microscopy was conducted to reveal the heteroepitaxy of the CFO/muscovite system. The robust magnetic behaviors against mechanical bending were characterized by hysteresis measurements and magnetic force microscopy, which maintain a saturation magnetization (Ms) of â¼120-150 emu/cm3 under different bending states. The large magnetostrictive response of the CFO film was then determined by digital holographic microscopy, where the difference of magnetostrction coefficient (Δλ) is -104 ppm. The superior performance of this bimorph is attributed to the nature of weak interaction between film and substrate. Such a flexible CFO/muscovite bimorph provides a new platform to develop next-generation flexible magnetic devices.
RESUMEN
Spintronics has captured a lot of attention since it was proposed. It has been triggering numerous research groups to make their efforts on pursuing spin-related electronic devices. Recently, flexible and wearable devices are in a high demand due to their outstanding potential in practical applications. In order to introduce spintronics into the realm of flexible devices, we demonstrate that it is feasible to grow epitaxial Fe3O4 film, a promising candidate for realizing spintronic devices based on tunneling magnetoresistance, on flexible muscovite. In this study, the heteroepitaxy of Fe3O4/muscovite is characterized by X-ray diffraction, high-resolution transmission electron microscopy, and Raman spectroscopy. The chemical composition and magnetic feature are investigated by a combination of X-ray photoelectron spectroscopy and X-ray magnetic circular dichroism. The electrical and magnetic properties are examined to show the preservation of the primitive properties of Fe3O4. Furthermore, various bending tests are performed to show the tunability of functionalities and to confirm that the heterostructures retain the physical properties under repeated cycles. These results illustrate that the Fe3O4/muscovite heterostructure can be a potential candidate for the applications in flexible spintronics.
RESUMEN
A new method of the chiral separation of three drugs such as sulpiride, amisulpride and mosapride was developed on the chiral stationary phase of amylose-tris-(5-chloro-2-methylphenylcarbamate) (ACMPC) by high performance liquid chromatography. The chromatographic behaviors of enantiomers of the three drugs were investigated in the mobile phases consisted of ethanol and n-hexane (containing 0.1% (v/v) diethylamine). The chromatographic conditions including the composition of the mobile phase, additives and temperature were further optimized for the chiral separation. The mechanism of racemic resolution for the mentioned drugs is discussed thermodynamically and structurally. The results indicated that these three chiral drugs could be separated on an ACMPC column under the optimum conditions, and their chiral resolutions were improved up to more than 1.5. The chromatographic parameters such as the retention factor kappa, separation factor a are presented, and the thermodynamic functions were calculated for the separation of the enantiomers of the three drugs. The method has been successfully applied to the determination of the enantiomers of the three drugs in tablets and blood serum. It is simple, reliable and accurate.