Articles you may be interested in 80% tunneling magnetoresistance at room temperature for thin Al-O barrier magnetic tunnel junction with CoFeB as free and reference layers J. Appl. Phys. 101, 09B501 (2007) ͑thick-nesses unit in nanometers͒ has been investigated. The tunnel magnetoresistance ͑TMR͒ shows a large increase up to 54.4% after annealing at 265°C due to the improved characteristic properties of the barrier and the interface between the barrier and the ferromagnetic electrodes. The TMR was observed to decrease drastically above the annealing temperature of 310°C accompanied by a notable increase of junction resistance and coercivity of the free layer. The amorphous Co 62 Fe 20 B 18 layers seem to behave as a barrier of diffusion, preventing the migration of Mn or Cu atoms into the interface between the barrier and the ferromagnetic layers. This may cause the drastic decrease of TMR due to the deterioration of the barrier and its interface with Co 62 Fe 20 B 18 layers. The observed crystallization in the amorphous Co 62 Fe 20 B 18 layers is considered to contribute to the increase in coercivity of the free layer.

We present detailed investigations of the electronic and optical properties of K3V5O14, including the band structure, density of states (DOS), population analysis, dielectric function, refractive index and second-order nonlinear susceptibilities. The calculations are performed using the ab initio pseudopotential density functional method combined with an anharmonic oscillator model, in which we employ the Perdew–Burke–Eruzerhof form of the generalized gradient approximation together with plane-wave basis sets for expanding the periodic electron density. From the band calculation, K3V5O14 is predicted to be an indirect band gap semiconductor. From the DOS and population analysis, we find that the bonding between K+ and V5O14 layers is mainly ionic while that between V and O is covalent. It is indicated that the hybridization of V-3d with the O-2p states is very important for the optical properties of K3V5O14. The calculated birefringence is large enough to achieve phase-matchable conditions, and our calculated second-harmonic-generation (SHG) coefficients agree with experimental results.

In this paper, a Super-twisting sliding-mode control method based on a nonlinear interference observer is proposed for the external perturbation of MEMS micromirrors during beam scanning. Developing a physical model of electrostatic MEMS micromirror, the Super-twisting sliding-mode control algorithm based on nonlinear interference observer is applied to the electrostatically driven MEMS scanning micromirror with side electrodes, with the demonstration on stability of the control system by Lyapunov theory. The method effectively improves the anti-disturbance performance of the system. The simulation results show that the Super-twisting sliding mode control method based on nonlinear disturbance observer can effectively enhance the disturbance inhibition of the system.