Terahertz time-domain spectroscopy is used to measure the complex conductivity of nanometer-thick gold films evaporated on silicon substrates in far-infrared spectral region from $0.2\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}2.7\phantom{\rule{0.3em}{0ex}}\mathrm{THz}$. With increasing film thickness a characteristic crossover an insulating conducting state via percolation transition observed. Of particular interest non-Drude behavior close transition. Whereas effective...

Efficient actuation is crucial to obtaining optimal performance from nanoelectromechanical systems (NEMS). We employed epitaxial piezoelectric semiconductors obtain efficient and fully integrated NEMS actuation, which based on exploitation of the interaction between strain built-in charge depletion. The underlying mechanism in these depletion-mediated becomes important only for devices with dimensions approaching semiconductor depletion lengths. induced forces are controlled electrically,...

Magnetic oscillations were studied in a single, lithographically patterned disk ( $8\ensuremath{\mu}\mathrm{m}\mathrm{diam}\ifmmode\times\else\texttimes\fi{}0.1\ensuremath{\mu}\mathrm{m}\mathrm{thick}$) of permalloy placed an in-plane biasing magnetic field, excited by subnanosecond pulses perpendicular field. Local changes the magnetization component detected time-resolved scanning magneto-optical Kerr microscopy, allowing direct observation nonuniform spatial evolution magnetization. It...

A method has been developed for performing fast time-resolved experiments with a scanning tunneling microscope. The uses the intrinsic nonlinearity in microscope's current versus voltage characteristics to resolve optically generated transient signals on picosecond time scales. ability combine spatial resolution of microscopy ultrafast optics yields powerful tool investigation dynamic phenomena atomic scale.

A remarkable number of methods for direct, real-space imaging in magnetic microscopy have been demonstrated over the past decade and a half, pace development shows no sign slowing. Our understanding magnetism increases as each striking new image surface thin-film magnetization is obtained. The continued high-performance information technologies also requires detailed study magnetostatics dynamics microscopic structures. Both fundamental curiosity practical interest now drive us toward...

Spatiotemporal magnetization reversal dynamics in a Ni(80)Fe(20) microstructure is studied using ps time scale scanning Kerr microscopy. Time domain images reveal striking change the associated with reduction switching when transverse bias field applied. Magnetization oscillations subsequent to are observed at two resonance frequencies, which sensitively depend on strength. The oscillation f = 2 GHz caused by damped precession of M, while lower frequency approximately 0.8 mode interpreted...

In biomedical applications ranging from the study of pathogen invasion to drug efficacy assays, there is a growing need develop minimally invasive techniques for single-cell analysis. This has inspired researchers optical, electrical, microelectromechanical and microfluidic devices exploring phenomena at level. this work, we demonstrate an electrical approach analysis wherein 1.6 GHz microwave interferometer detects capacitance changes (ΔC) produced by single cells flowing past coplanar...

Sensors in optical cavities can be used for measuring acceleration, fields, and particles. New research reveals a record sensitivity detecting small amounts of torque within cavities, useful magnetic fields.

Controlling Magnetic Noise Ferromagnetic materials contain a number of magnetic domains, with individual domains switching stochastically as the field strength is increased. As memory elements shrink in size, it important to understand, and ultimately control, this noise. Using vortex core integrated nanomechanical torsion balance, Burgess et al. (p. 1051 , published online 17 January) created two-dimensional map potential within sample nanoscale resolution. Moreover, introducing geometric...

Optomechanical transduction is demonstrated for nanoscale torsional resonators evanescently coupled to optical microdisk whispering gallery mode resonators. The on-chip, integrated devices are measured using a fully fiber-based system, including tapered and dimpled fiber probe. With thermomechanically calibrated optomechanical noise floor down 7 fm/sqrt(Hz), these open the door wide range of physical measurements involving extremely small torques, as little 4x10^-20 N*m.

The dynamic spin modes observed in magnetic vortex structures are shown to depend strongly on the nature of initial excitation by a transient pulse field. In submicrometer-sized Permalloy disks, when uniform perpendicular field is used perturb magnetization, radial standing-wave excited; whereas if an in-plane used, angular or azimuthal formed. existence core responsible for frequency splitting modes, as demonstrated through comparison micromagnetic simulations ring geometry.

We present details of an apparatus for capacitive detection biomaterials in microfluidic channels operating at microwave frequencies where dielectric effects due to interfacial polarization are minimal. A circuit model is presented, which can be used adapt this system use other applications and identify ones it would not suitable. The based on a coupled transmission line resonator integrated into interferometer. At 1.5 GHz the capable detecting changes capacitance 650 zF with 50 Hz...

An advanced deposition technique known as glancing angle (GLAD) [K. Robbie, J. C. Sit, and M. Brett, Vac. Sci. Technol. B 16, 1115 (1998); K. Robbie U.S. Patent No. 5,866,204 (filed 1999)] has been used to fabricate periodic arrays of magnetic pillars randomly seeded helices, posts, chevrons. Because the nature initial film nucleation, GLAD process normally distributes posts on substrate surface. We can grow microstructures by suppressing randomness inherent within nucleation stage growth....

We report the demonstration of a magneto-optic sampling technique that allows for detection picosecond electrical pulses propagating down microstrip transmission line. A unique feature method is it directly measures current in ultrashort pulses. The based on time-resolved Faraday effect Bi-substituted yttrium-iron-garnet (Bi-YIG) film. detailed magnetic response found to be excellent agreement with Bloch-Bloembergen equations. bandwidth system has been demonstrated scale ferromagnetic...

The application of picosecond magneto-optic sampling techniques to studies the magnetization dynamics thin-film recording heads is described. Time-resolved measurements are performed using stroboscopic scanning Kerr microscopy. A Faraday probe used monitor coil excitation current with same optical setup, yielding a direct measure magnetic propagation delay through head. This found have marked spatial dependence across face pole tips. As an aid visualization dependence, scanned images polar...

Femtosecond spectroscopic measurements of optically induced magnetization are performed on new type-II ZnTe/${\mathrm{Cd}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Mn}}_{\mathit{x}}$Se diluted-magnetic-semiconductor heterostructures consisting magnetic quantum wells confined by nonmagnetic barrier layers. The formation and evolution electron-based bound polarons in the is observed through static time-domain experiments. Energy-dependent spin dynamics ultrashort time scales seen to vary...

Patterned arrays of ceramics have been fabricated using electron‐beam lithography (EBL) and a metallopolymer resist. Highly ordered dots, bars (see scanning electron microscopy time‐of‐flight secondary ion mass spectrometry images in the Figure), curved lines rich Fe Co are direct‐written on films highly metallized cobalt‐clusterized polyferrocenylsilane. Subsequent pyrolysis leads to ferromagnetic ceramics.

A universal, torque-mixing method for magnetic resonance spectroscopy is presented. In analogy to detection by induction, the transverse component of a precessing dipole moment can be measured in sensitive broadband spectroscopy, here using resonant mechanical torque sensor. Unlike amplitude allows equilibrium properties monitored simultaneously with spin dynamics. Comprehensive electron spectra single-crystal, mesoscopic yttrium iron garnet disk at room temperature reveal assisted switching...

Charge-carrier spin scattering in diluted-magnetic-semiconductor multiple quantum wells is directly observed through the circular polarization of luminescence a femtosecond time-resolved measurement. This represents new short-time regime for direct spin-relaxation studies. Separate observations electron and hole relaxation are accomplished by varying applied magnetic field. Surprisingly, spin-flip rates these systems appear to be independent extremely strong spin-spin--exchange interaction...

Time-resolved microscopy enables valuable new measurements of the dynamics resonance and relaxation in a range magnetic systems. An overview scope applications to ferromagnetic microstructures is presented. These include observations spatially nonuniform modes oscillation, studies magnetization reversal, characterizations speed recording devices.

We report the fabrication of high-resolution sub 50 nm patterns by electron beam lithography using epoxy novolak SU-8 2000 resist formulation. The minimum linewidth achieved is on order 30 and corresponds to a threefold reduction in over previous reports describing similar chemistries. Our results also show that it possible fabricate dense linear grating elements without proximity correction. dry etch resistance native was found be nearly twice poly(methylmethacrylate), making ideal for...

Terahertz (THz) pulses propagating on a metal-wire waveguide are used to perform terahertz time-domain spectroscopy of lactose powder dispersed top the wire. The THz generated by photoconductive switch at one end metal wire and detected other electro-optic sampling in ZnTe crystal that can be moved parallel axis A large enhancement peak amplitude signal is observed contacting electrodes switch. propagation characteristics pulse along near its studied. Potential applications discussed.