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1
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Non-Destructive Material Homogeneity Evaluation Using Scanning Millimeter Wave Microscopy

100%
Laurinavičius A., Anbinderis T., Ikonikova J., Prishutov Y.
Acta Physica Polonica A
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2008
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vol. 113
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issue 3
1051-1054
EN
Millimeter wave bridge technique for non-destructive material homogeneity characterization is described. The idea of this technique is the local excitation of the millimeter waves in the testing material and the measurement of the transmitted (reflected) wave amplitude and phase in different places of it, i.e. the material plate is scanned by the beam of the millimeter waves. The results of the homogeneity measurements for dielectric wafers according to dielectric constant anisotropy are presented. The measurement technique sensitivity is discussed.
2
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Charge Carrier Heating Effect in Porous Silicon Structures Investigated by Microwaves

80%
Gradauskas J., Šatkovskis E., Česnys A., Stupakova J., Sužiedėlis A.
Acta Physica Polonica A
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2008
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vol. 113
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issue 3
993-996
EN
Diode-like samples, containing porous silicon structures, were investigated by microwave radiation pulses. The resistance of the samples and electromotive force arising over the samples placed in a section of waveguide was measured. Reduction of resistance of the samples was observed with increase in microwave power. More complicated shape of the electromotive force dependence on pulse power was found. It is shown that both effects could be explained by models based on a concept of carrier heating by microwave radiation.
3
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Microwave Conductivities of Polymer Films Doped with BEDT-TTF Polyiodides

80%
Staerk D., Helberg H. W., Ulański J., Jeszka J. K.
Acta Physica Polonica A
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1995
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vol. 87
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issue 4-5
797-800
EN
Conducting reticulate doped polymeric films containing BEDT-TTF iodide crystalline networks have been annealed in order to transform the crystallites into crystal phases with metallic conductivity. The microwave conductivity of these films was measured before and after annealing. The temperature dependence of the conductivity changes dramatically with op­timal annealing temperatures and times. This change in the behavior cor­responds to the transformation of the α-phase into the superconducting α_{t}-phase observed in (BEDT-TTF)_{2}I_{3} single crystals.
4
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New Insights into the Reentry Behavior of Deuterated DCNQI Cu-Salts by Microwave Measurements

80%
Predak S., Helberg H., Von Schütz J.
Acta Physica Polonica A
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1995
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vol. 87
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issue 4-5
791-795
EN
The microwave conductivity of the copper salt of DCNQI (N,N'-Di­cyanoquinodiimine) with two methyl side groups (undeuterated, h_{8}), the fully deuterated salt (d_{8}), the salt with only the methyl groups deuterated and of alloys of undeuterated and deuterated salts was measured. The mi­crowave conductivity (10.2 GHz) qualitatively follows the dc conductivity. The difference is in the window of diminished conductivity between phase transition and reentry, where the microwave conductivity is higher than the dc conductivity. This indicates the existence of a crystal fraction with higher (metallic) conductivity (portion: ≈ 1‰) not seen by dc methods.
5
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Carrier Heating Efficiency in Optically Detected Cyclotron Resonance Experiment

80%
Dedulewicz S., Godlewski M.
Acta Physica Polonica A
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1993
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vol. 84
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issue 3
535-537
EN
Monte Carlo calculations of carrier heating efficiency in optically detected cyclotron resonance experiment are presented. It is shown that electrons accelerated by microwave electric field gain energy sufficient for impact ionization of shallow centers and for exciton dissociation. It is also explained why very sharp thresholds for impact processes were observed in the optically detected cyclotron resonance investigations.
6
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NMR Study of (Sr,Ba,La)_2Fe_{1+y}Mo_{1-y}O_6 Double Perovskites

80%
Zając D., Kapusta C., Riedi P., Sikora M., Oates C., Rybicki D., De Teresa J., Serrate D., Marquina C., Ibarra M.
Acta Physica Polonica A
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2004
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vol. 106
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issue 5
759-765
EN
The ^{95}Mo and ^{97}Mo NMR spin-echo study of (Sr,Ba,La)_2Fe_{1 +y}Mo_{1-y}O_6 double perovskites is reported. Powder samples of Ba_{1.44}Sr_{0.36}La_{0.2}FeMoO_6 and (Ba_{0.8}Sr_{0.2})_{2-2x}La_x#_x Fe_{1+y}Mo_{1-y}O_6, where# denotes vacancies, for: x=0, y=0; x=0.1, x=0.2 and x=0.3, y=0 and y=0.2 were measured at 4.2 K and no applied magnetic field. NMR signals are observed at 55-100 MHz for the main line and 30-55 MHz for low-frequency satellite. The main line and the satellite are attributed to the ideal and defect positions of Mo atoms. La and vacancy doping introduce more defects, however, increasing the Fe/Mo ratio decreases the amount of defect Mo sites. La doping causes a satellite pattern at the high frequency side of the spectrum, which is related to different numbers of the La next neighbours. The effect is attributed to an increase in the electron density and the corresponding magnetic moment at the adjacent Mo sites and reveals a local character of the electron doping.
7
Content available remote

Influence of Magnetic Field on Detection Properties of Planar Microwave Diodes

61%
Sužiedėlis A., Ašmontas S., Požela J., Gradauskas J., Nargelienė V., Paškevič Č., Derkach V., Golovashchenko R., Goroshko E., Korzh V., Anbinderis T.
Acta Physica Polonica A
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2011
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vol. 119
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issue 2
218-221
EN
The results of experimental investigation of detection properties of the planar microwave diodes of various configuration on DC magnetic field are presented in this paper. The detection of microwave radiation was measured at 51 GHz, 72 GHz and 144 GHz frequencies. The magnetic field was applied in plane and perpendicularly to the plane of the diodes. The experiment was performed at room temperature. Dependence of the detected voltage of the diodes on the magnetic field had asymmetric character with respect to the polarity of the magnetic field. This fact allowed us to suspect the magnetic rectification influencing the detected voltage. Therefore, average value of the detected voltage with respect to the polarity of the applied magnetic field gives its dependence on the applied magnetic field.
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