Superconductive Controlled Weak-Links

Abstract

The value of electron microscopy in the study of organic crystals is reviewed, together with its limitations in terms of radiation damage. Tne mechanism of formation and growth of crystals on a substrate is discussed, on the basis of electron microscopic observations, of both small crystals and the molecular structure of growth boundaries. Several examples of polycyclic hydrocarbons and phtnalocyanines are described. A distinction is made between the information obtainable about disorder in a crystal, and precise measurements made by electron crystallography involv.ng structural averaging. rhe Electron Microscope (New York Plenum) Buseck P R, Cowley J M and Eyring L 1988 High R~solution Transmission Elecrmn Microscopy (Oxford Oxford University Press) Spence J C H 1981 Erperimental High Resolution Electron Microscopy (Oxford: Clarendon) Wilson A J C 1992 InternarioMl Tables for Costallography (Dordrecht: Kluwer) Symonds M C R 1982 Ultramicmxopy 10 15 Fryer J R and Holland F M 1984 Pmc. R. Soc. A 393 352 P 1980 Ulframicroscopy 5 195 Kobayashi T and Reimer L 1975 Bull. Inst. Chem. Res. Kyoto Univ. 53 105 Siegle G 1972 Nalu?farschwzg a 27 325 lntemational Study Group 1986 J. Microsc. 141 385 Salih S M and Cossletl V E 1975 J, Micmsc. 105 269 Salih S M and Cossletl V E 1974 Phil. Mag. 30 225 Fryer J R 1987 Ulframicroscopy 23 321 Vesely D and Downing K H 1990 Elecrmn Crystallography of Organic Molecules ed J RFryer and D L Dorset (Dordrecht: Kluwer) p 361 145 139 269 J. Appl. Phys. 48 3900 Dorset D L and Turner J N 1976 Narunvissenschnflen 63 Henderson R and Glaeser R M 1985 Ultramicroscopy 16 Downing K H and Glaeser R M 1986 Ultramicroscopy 20 Vincett P S , Barlow W A and Roberts G G 1977 Fryer J R and Ewins C 1992 Phil. Mag. A 66 889 Debe M K 1982 J. Vac. Sci. Technol. 21 74 Fan P L. Larson D C and L a b s M M 1972 Thin Solid Fi(mS.12 s3-7 Donaldson D M. Robertson J M and White J G 1953

Quasiparticle injection effects in YBa2Cu3Ox-based planar structures at high operating temperatures

“…In this case the generated "normal" overheated zone in the gatecontact area propagates along the bridge with thermal speed, yielding a voltage drop proportional to the length of the bridge. The switching time of such a system is in the kHz range and below and the operation mode is latching [2,3]. In the present stud?…”

“…In previous studies of the injection effect in controlled weak-link structures [2][3][4] narrowest part of the bridge was an order of magnitude larger than the length of the gate. In this case the generated "normal" overheated zone in the gatecontact area propagates along the bridge with thermal speed, yielding a voltage drop proportional to the length of the bridge.…”

“…Due to structural simplicity, large current and voltage gain and relatively high operating speed, the injection-controlled structures are promising for practical applications like switching or transistor-like elements. A current gain of 95 was found in low-T¢ weak-link structures [2,3]. A first study of quasiparticle injection in HTS YBCO/A1 structures shows a current gain of 5-7 at 4.2 K [4].…”