The use of a piezoelectric force sensor in the magnetic force microscopy of thin permalloy films.

A piezoelectric force sensor is suggested for magnetic force microscopy (MFM) purposes. Added between the piezoelectric resonator and the magnetic probe is a mechanical force amplifier in the form of a thin, long resonant arm with an integral micro-rod whereby the amplitude of the force acting on the probe is amplified by a factor of 20 to 40 at a low noise level. When the sensor was operated in air, its noise floor was found to be 1.

Magnetic properties of biofunctionalized iron oxide nanoparticles as magnetic resonance imaging contrast agents.

One of the future applications of magnetic nanoparticles is the development of new iron-oxide-based magnetic resonance imaging (MRI) negative contrast agents, which are intended to improve the results of diagnostics and complement existing Gd-based contrast media. Iron oxide nanoparticles designed for use as MRI contrast media are precisely examined by a variety of methods: powder X-ray diffraction (XRD), transmission electron microscopy (TEM), Raman spectroscopy, Mössbauer spectroscopy and zero-field nuclear magnetic resonance (ZF-NMR) spectroscopy. TEM and XRD measurements reveal a spherical shape of the nanoparticles with an average diameter of 5-8 nm and a cubic spinel-type crystal structure of space group -3.

Contrast Agents Based on Iron Oxide Nanoparticles for Clinical Magnetic Resonance Imaging.

Magnetic resonance imaging (MRI) is one of the most perspective methods of noninvasive visualization in medicine, and use of contrast agents significantly its potentialities extends. Iron oxide nanoparticles are promising contrast agents, but in fact all the data on their efficiency were obtained in high-field tomographs for experimental animals. We studied the possibility of using magnetic nanoparticles for MRI visualization of rat brain glioblastoma at the most common clinical field 1.

Relaxation Properties of Contrast Media for MRI Based on Iron Oxide Nanoparticles in Different Magnetic Fields.

We studied dependences of T2 relaxation time on magnetic field and concentration of nanoparticles. It was found that nanocontrast media are effective under the influence of the magnetic fields in the range 0.3-7 T.

Inertial motor on a single piezoelectric actuator for a low-temperature near-field scanning optical microscope.

The impact of such factors as the shape of the applied voltage pulse, the friction force, and the mass of the movable part on the motor operation at low temperatures is experimentally investigated. Important added features in the motor design are support springs. These springs prevent one part of the slider clamp from shifting relative to the other during motion.

Periodic structures on liquid-phase smectic A, nematic and isotropic free surfaces.

The free boundary of smectic A (SmA), nematic and isotropic liquid phases were studied using a polarized optical microscope, an interferometric surface structure analyzer (ISSA), an atomic force microscope (AFM) and a scanning near-field optical microscope (SNOM). Images of the SmA phase free surface obtained by the polarized microscope and ISSA are in good correlation and show a well-known focal domain structure. The new periodic stripe structure was observed by scanning near-field optical microscopy on the surface of the smectic A, nematic and isotropic phases.

Nanoprofilometry study of focal conic domain structures in a liquid crystalline free surface.

This work presents the first high-resolution nanoprofilometry study consisting of nanoscale resolution surface profile measurements and high-quality visualization of a the free surface of a liquid crystal-air boundary. The capabilities of this new experimental method, as applied for liquid crystal free boundaries, are discussed. The formation of focal conic domain structures at the smectic-A-air free boundary was detected and studied.

Anomalous multi-order Raman scattering in LaMnO3: a signature of quantum lattice effects in a Jahn-Teller crystal.

The multi-order Raman scattering is studied up to fourth order for a detwinned LaMnO3 crystal. Based on a comprehensive data analysis of the polarization-dependent Raman spectra, we show that the anomalous features in the multi-order scattering could be the sidebands on the low-energy mode at about 25 cm(-1). We suggest that this low-energy mode stems from the tunneling transition between the potential energy minima arising near the Jahn-Teller Mn(3+) ion due to the lattice anharmonicity and that the multi-order scattering is activated by this low-energy electronic motion.

Collective behavior of light-induced droplets in smectic membranes.

Collective behavior and organization of droplets in thin smectic membranes were investigated using polarized light microscopy. Droplets were nucleated in membranes by light illumination. We observed the formation of periodic hexagonal and square lattice structures from droplets at large droplet concentration.