of the original manuscript:Hedayati, M.K.; Javaherirahim, M.; Mozooni, B.; Abdelaziz, R.; Tavassolizadeh, A.; Chakravadhanula, V.S.K.; Zaporojtchenko, V.; Strunkus, T.; Faupel, F.; Elbahri, M.: Design of a Perfect Black Absorber at Visible Frequencies Using Plasmonic MetamaterialsIn: Advanced Materials (2011) Submitted to 2 ((During the course of the last decade, trends to achieve perfect absorbers increased tremendously due to the huge interest in development of the materials for harvesting solar energy. However up to date all of the applied methods (perforated metallic films, [1][2][3] grating structured systems [4][5][6][7] , and metamaterials [8][9][10][11][12][13][14] ) are costly and suffer from a lack of flexibility.Furthermore their absorbance is limited to a narrow spectral range which makes their application for a broad range of frequencies impossible.Here we demonstrate design, fabrication and characterization of a perfect plasmonic absorber in a stack of metal and nanocomposite showing almost 100% absorbance spanning a broad range of frequencies from ultraviolet to the near infrared. The fabrication technique of our metamaterial is pretty simple, cost effective and compatible with current industrial methods of MEMS which make our proposed system an outstanding candidate for high efficiency absorber materials.Thick metallic film are known as an excellent mirror but when they are structured, the reflectance fades away because the light gets absorbed by the excitation of the conduction electrons by electromagnetic waves which is generally known as plasmon resonance.[1] This concept has been used in the last few decades to realize highly absorbing systems in diverse areas of the electromagnetic spectrum but these works were either successful only for a very narrow range of frequencies [7,[14][15][16] or the absorbance was distant from that of blackbody materials [11] .Not only the metallic film supports plasmon resonances but also the metallic nanoparticles show high absorption due to its localized particle plasmon resonance (Mie resonance) [17][18] Indeed, the resonance of these particles embedded in different matrices has been extensively studied within the last decade and it is well known that the resonance bandwidth depends on the size, shape, density and distribution of the nanoparticles. [17][18] Indeed, a highly dense nanocomposite gives rise to a very broad-band absorption due to the excitation of the localized plasmon resonance of the nanoparticles by visible light. [19] In contrast to the Submitted to 3 expectation for the absorption behavior of a metal/polymer nanocomposite, we have recently shown that nanocomposites with low filling factor in a proximity to a thin metallic film can even enhance the optical transmission of the system due to the plasmonic coupling of the film and the nanoparticles which mainly result in a reflection/scattering reduction of the system by dipole/image interaction. [20] However, rising the distance between the metallic film and the nanoparticles by adding a space...

Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of −3.2 kA/m under a 0.2×10-3 strain, gauge factors of 2294 and −311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30±0.2sans-serifμm using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150±30 and −260 for tensile and compressive stresses, respectively, under a −3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

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