摘要:

We present the results of an analytical study of phase locking in externally loaded two-dimensional Josephson junction ladder arrays with small, but non-vanishing ring inductances. A Lyapunov stability based condition is found controlling realization of the radiating in-phase oscillation regime. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120701

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Long chains of 400 nm diam Co dots prepared by combined electron-beam lithography exhibit interesting magnetotransport properties. The magnetoresistance of the chains of dots is markedly different from single Co films, indicating a strongly modified magnetization reversal process. Magnetic force microscopy (MFM) shows that, after magnetic saturation, in the remanent state the single-domain dots are all oriented with their magnetic moment along the chain. A comparison of the magnetoresistance and the MFM reveals that the magnetization reversal occurs by coherent rotation of the magnetic moment in the single-domain dots forming the chain. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120702

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

A low dielectric constant polymer, poly(tetrafluoro-p-xylylene) (VT-4) was synthesized by a chemical vapor polymerization process using 4,5,7,8,12,13,15,16-octafluoro-[2.2]-paracyclophane as a precursor. The VT-4 polymer has a dielectric constant of 2.42 and a dielectric loss of 0.008 at 1 MHz, perpendicular to the plane of the film. Thermal stability of VT-4 satisfied theSEMATECHcriteria, exhibiting an onset of degradation at 460 °C, and 1&percent; weight loss at 480 °C in an argon environment. The x-ray diffraction data suggest a disordered semicrystalline polymer as-deposited (at ∼12 °C). The crystalline phase became more ordered due to a decrease in thedspacing from 4.850 to 4.594 Å and an increase in the percent crystallinity from 39&percent; as-deposited to 66&percent; after successive postdeposition anneals to 300 °C. Optical measurements showed a highly anisotropic thin film withne&at;630 nm=1.601 andn0&at;630 nm=1.471, progressively becoming more negatively birefringent after postdeposition anneals, reaching a plateau at ∼250 °C, due to the polymer chain becoming more conformationally ordered. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120703

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Low-temperature (200 °C) sputter deposition ofSrTiO3(STO) thin films by using ultrahigh-density ceramic target enabled us to fabricate capacitors on polyimide-isoindroquinazoline dione (PIQ)- or benzocyclobutene (BCB)-coated alloy substrates. Complex impedances of the capacitors were analyzed. Capacitances of the0.01 mm2area capacitors with 200-nm-thick STO films were around 22 pF and were not dependent on frequency up to 8 GHz. Leakage-current densities of the films were lower than10−6 A/cm2at an applied voltage of 10 V and dielectric loss tangents were lower than10−6.©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120704

出版商:AIP    

年代:1998

数据来源: AIP

摘要:

Electrofreezing is an effect where an electrostatically charged surface in contact with a supercooled liquid or an externally applied electric field significantly enhances nucleation of the solid phase. The electrofreezing effect has been used as a tool to nucleate ice and heavy ice crystals in free-growth experiments at supercooling greater than 1.5 °C. In order to nucleate ice crystals at smaller supercooling, we describe a device which uses a combination of a thermoelectric cooler and the electrofreezing effect. This system has been used to nucleate crystals at a supercooling down to 0.1 °C, but this figure is only limited by the temperature stability of the growth medium. ©1998 American Institute of Physics.

ISSN:0003-6951    

DOI:10.1063/1.120705

出版商:AIP    

年代:1998

数据来源: AIP