Measurement of trap density in dielectric film

Method uses basic circuit to examine quality and trap density of film used in insulated gate field effect transistors. Data are measured as function of performance and life expectancy

Thermomagnetic recording and magneto-optic playback system having constant intensity laser beam control

A system is developed for maintaining the intensity of a laser beam at a constant level in a thermomagnetic recording and magneto-optic playback system in which an isotropic film is heated along a continuous path by the laser beam for recording. As each successive area of the path is heated locally to the vicinity of its Curie point in the presence of a controlled magnetic field, a magneto-optic density is produced proportional to the amplitude of the controlled magnetic field. To play back the recorded signal, the intensity of the laser beam is reduced and a Faraday or Kerr effect analyzer is used, with a photodetector, as a transducer for producing an output signal

Starting Circuit for Vapor Lamps and the Like-Patent

Starting circuit design for initiating and maintaining arcs in vapor lamp

The Effects of the Foreign Direct Investment: Liberalisation on Pakistan

Pakistan for many years maintained strict controls on foreign direct investment. However, over the past decade controls on foreign investment in manufacturing have diminished sharply, though less so for the service sector. The government continues to impose restrictions on foreign trade, which adversely affect foreign direct investors in several ways. Nonetheless, Pakistan has moved a substantial distance toward liberalising direct foreign investment. There are two obvious policy issues related to foreign investment raised by these developments. First, should Pakistan proceed further toward liberalisation and at what pace? Second, with a liberalised investment sector, should Pakistan become an active protagonist among developing countries for a multilateral agreement on investment? This paper explores the macroeconomic effects of foreign direct investment liberalisation on developing countries that have yet to substantially and fully liberalise. The principal focus will be on relatively short term effects—those changes that will occur between one and five years after liberalisation, although long-term effects are also discussed. Unfortunately, very little is known about the repercussions of foreign direct investment liberalisation on host economies. There is a rich literature on the effects of trade policy liberalisation on macroeconomic variables. Considerable scholarly work has been done on the impact of foreign direct investment on host economies under existing investment regimes. However, for a variety of reasons discussed below the link between investment liberalisation and macroeconomic performance has received scant attention from researchers. This study summarises a few pieces of this small body of research on foreign direct investment, but this only takes us part of the way. As Sebastian Edwards noted in a recent study, “applied economists often ask too much of their data sets, and try to extract information that is simply not there” [Edwards (1993)]. With that caveat in mind, the paper takes two approaches to achieving its stated purpose of exploring the macroeconomic effects of investment liberalisation.

A survey of fractured SrTiO3_3 surfaces: from the micro-meter to nano-meter scale

Cross-sectional scanning tunneling microscopy was utilized to study fractured perovskie oxide surfaces. It was found for the non-cleavable perovskite oxide, SrTiO$_{3}$, that atomically flat terraces could be routinely created with a controlled fracturing procedure. Optical and scanning electron microscopy as well as a profilometer were used to obtain the information from sub-millimeter to sub-micrometer scales of the fractured surface topography.Comment: 9 pages, 4 figure

Manganese bismuth films with narrow transfer characteristics for Curie-point switching

Manganese bismuth films having improved characteristics for recording information in analogue form, can be produced by a vacuum deposition of Bi and Mn with an atomic ratio of Mn to Bi between 2 and 3.5 or 1.4 and 1.6, followed by a specialized heat treatment which includes very brief exposure to a temperature between about 275 deg and 300 C. Similar MnBi films can be produced more reliably and reproducibly if the initial Bi layer is annealed prior to deposition of the Mn layer. Such an annealing step renders most other factors of the processing relatively non-critical. Deposition of both initial layers is preferably carried out in a vacuum approaching 10 to the -8th power Torr

Magneto-optic detection system with noise cancellation

In a magneto-optic readout system, a polarized beam of light from a laser is subjected to the magneto-optical effect of a magnetic record medium, and then passed through an analyzer which resolves the beam into two orthogonal vector components so oriented that the two components are of equal amplitude when the angle of rotation due to the magneto-optic effect is zero. Separate photodetectors produce two output signals which are proportional to the amplitudes of the vector components. The two output signals are combined in a differential amplifier through separate logarithmic transfer circuits to produce an output signal proportional to the ratio of the two original detector signals

Nanometer-scale striped surface terminations on fractured SrTiO3_{3} surfaces

Using cross-sectional scanning tunneling microscopy on in situ fractured SrTiO$_{3}$, one of the most commonly used substrates for the growth of complex oxide thin films and superlattices, atomically smooth terraces have been observed on (001) surfaces. Furthermore, it was discovered that fracturing this material at room temperature results in the formation of stripe patterned domains having characteristic widths (~10 nm to ~20 nm) of alternating surface terminations that extend over a long-range. Spatial characterization utilizing spectroscopy techniques revealed a strong contrast in the electronic structure of the two domains. Combining these results with topographic data, we are able to assign both TiO$_{2}$ and SrO terminations to their respective domains. The results of this proof-of-principle experiment reveal that fracturing this material leads to reproducibly flat surfaces that can be characterized at the atomic-scale and suggests that this technique can be utilized for the study of technologically relevant complex oxide interfaces.Comment: 15 pages, 4 figure

Grain Boundary Loops in Graphene

Topological defects can affect the physical properties of graphene in unexpected ways. Harnessing their influence may lead to enhanced control of both material strength and electrical properties. Here we present a new class of topological defects in graphene composed of a rotating sequence of dislocations that close on themselves, forming grain boundary loops that either conserve the number of atoms in the hexagonal lattice or accommodate vacancy/interstitial reconstruction, while leaving no unsatisfied bonds. One grain boundary loop is observed as a "flower" pattern in scanning tunneling microscopy (STM) studies of epitaxial graphene grown on SiC(0001). We show that the flower defect has the lowest energy per dislocation core of any known topological defect in graphene, providing a natural explanation for its growth via the coalescence of mobile dislocations.Comment: 23 pages, 7 figures. Revised title; expanded; updated reference