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| Author | Decca, R.S.; Drew, H.D.; Maiorov, B.; Guimpel, J.; Osquiguil, E.J. | ||||
| Title | Inducing superconductivity at a nanoscale: Photodoping with a near- field scanning optical microscope | Type | Journal Article | ||
Year  |
1999 | Publication | Journal of Microscopy | Abbreviated Journal | J. Microsc. |
| Volume | 194 | Issue | 2-3 | Pages | 407-411 |
| Keywords | High critical temperature superconductors; Near-field microscopy; Photoconductivity; Photoinduced superconductivity; barium; copper derivative; gadolinium; nanoparticle; conductance; conference paper; crystal structure; crystallography; density; fiber optics; film; illumination; magnetic field; photoactivation; priority journal; reflectometry; scanning near field optical microscopy; temperature | ||||
| Abstract | The local modification of an insulating GdBa2Cu3O6.5 thin film, made superconducting by illumination with a near-field scanning optical microscope (NSOM), is reported. A 100-nm aperture NSOM probe acts as a sub- wavelength light source of wavelength ?(exc)=480-650 nm, locally generating photocarriers in an otherwise insulating GdBa2-Cu3O6.5 thin film. Of the photogenerated electron-hole pairs, electrons are trapped in the crystallographic lattice, defining an electrostatic confining potential to enable the holes to move. Reflectance measurements at ? = 1.55 ?m at room temperature show that photocarriers can be induced and constrained to move on a ?? 200 nm scale for all investigated ?(exc). Photogenerated wires present a superconducting critical temperature T(c) = 12 K with a critical current density J(c) = 104 A cm-2. Exploiting the flexibility provided by photodoping through a NSOM probe, a junction was written by photodoping a wire with a narrow (? 50 nm) under-illuminated gap. The strong magnetic field modulation of the critical current provides a clear signature of the existence of a Josephson effect in the junction. | ||||
| Address | Ctro. Atomico Bariloche and Inst. B., Comision Nac. de Energia Atomica, 8400 S. C. de Bariloche, RN, Argentina | ||||
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| ISSN | 00222720 (ISSN) | ISBN | Medium | ||
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| Notes | Cited By (since 1996): 1; Export Date: 17 April 2009; Source: Scopus; CODEN: JMICA; doi: 10.1046/j.1365-2818.1999.00540.x; Language of Original Document: English; Correspondence Address: Decca, R.S.; Laboratory for Physical Sciences; Department of Physics; University of Maryland College Park, MD 20742, United States; email: rdecca@physics.umd.edu; References: Decca, R.S., Drew, H.D., Empson, K.L., Investigation of the electric-field distribution at the subwavelength aperture of a near-field scanning optical microscope (1997) Appl. Phys. Lett., 70, pp. 1932-1934; Decca, R.S., Drew, H.D., Maiorov, B., Osquiguil, E., Guimpel, J., Photoinduced superconducting nanowires in GdBa2-Cu3O6.5 films (1998) Appl. Phys. Lett., 72, pp. 120-122; Endo, T., Hoffmann, A., Santamaria, J., Schuller, I.K., Enhancement of persistent photoconductivity by uv excitation in GdBa2Cu3O6.3 (1996) Phys. Rev. B., 54, pp. 3750-3752; Federici, J.F., Chew, D., Welker, B., Savin, W., Gutierrez-Solana, J., Fink, T., Wilber, W., Defect mechanism of photoinduced superconductivity in YBa2Cu3O6+x (1995) Phys. Rev. B, 52, pp. 15592-15597; Ginsberg, D.M., (1996) Physical Properties of High Temperature Superconductors V, , World Scientific, Singapore; Guimpel, J., Maiorov, B., Osquiguil, E., Nieva, G., Pardo, F., Interrelation between persistent photoconductivity and oxygen order in GdBa2Cu3Ox thin films (1997) Phys. Rev. B, 56, pp. 3552-3555; Kirilyuk, A.I., Kreines, N.M., Kudinov, V.I., (1990) Pis'ma Zh. Eksp. Teor. Fiz., 52, p. 696. , Frozen photoconductivity in YBaCuO films; JETP Lett., 52, pp. 49-54; Krylov, I.P., (1990) Pis'ma Zh. Eklsp. Teor. Fiz., 52, p. 1049; Mechanism for the frozen photoconductivity of YBa2Cu3O7-? JETP Lett., 52, pp. 442-446; Kudinov, V.I., Chaplygin, I.L., Kirilyuk, A.I., Keines, N.M., Laiho, R.L.E., Ayache, C., Persistent photoconductivity in YBa2Cu3O6+x films as a method of photodoping toward metallic and superconducting phases (1993) Phys. Rev. B, 47, pp. 9017-9028; Lederman, D., Hasen, J., Schuller, I.K., Photoinduced superconductivity and structural changes in high temperature superconducting films (1994) Appl. Phys. Lett., 64, pp. 652-654; Nakamura, O., Fullerton, E.E., Guimpel, J., Schuller, I.K., High Tc thin films with roughness smaller than one unit cell (1992) Appl. Phys. Lett., 60, pp. 120-122; Nieva, G., Osquiguil, E., Guimpel, J., Maenhoudt, M., Wuyts, B., Bruynseraede, Y., Maple, M.P., Schuller, I.K., Photo-induced changes in the transport properties of oxygen-deficient YBa2Cu3Ox (1992) Phys. Rev. B, 46, pp. 14249-14252; Orenstein, J., Thomas, G.A., Millis, A.J., Cooper, S.L., Rapkine, D.H., Timusk, T., Schneemeyer, L.F., Waszczak, J.V., Frequency-and temperature-dependent conductivity in YBa2Cu3O6+x crystals (1990) Phys. Rev. B, 42, pp. 6342-6362; Osquiguil, E., Maenhoudt, M., Wuyts, B., Bruynseraede, Y., Photoexcitation and oxygen ordering in YBa2Cu3Ox films (1994) Phys. Rev. B, 49, pp. 3675-3678; Tinkham, M., (1996) Introduction to Superconductivity, 2nd Edn., , McGraw-Hill, New York | Approved | no | ||
| Call Number | BT @ osquigui @ | Serial | 376 | ||
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| Author | Lederman, D.; Hasen, J.; Schuller, I.K.; Osquiguil, E.; Bruynseraede, Y. | ||||
| Title | Photoinduced superconductivity and structural changes in high temperature superconducting films | Type | Journal Article | ||
| Year |
1994 | Publication | Applied Physics Letters | Abbreviated Journal | |
| Volume | 64 | Issue | 5 | Pages | 652-654 |
| Keywords | Annealing; Electric conductivity measurement; Lighting; Oxygen; Praseodymium compounds; Quenching; Semiconducting films; Structure (composition); Superconductivity; Thermal effects; Thin films; Yttrium compounds; Contraction; Oxygen vacancy; Photoinduced superconductivity; Stoichiometry; Superconducting critical temperature; High temperature superconductors | ||||
| Abstract | The illumination of PryGd1-yBa2Cu 3Ox semiconducting and superconducting thin films increases their critical temperatures and decreases their normal state resistivities if and only if the films are oxygen deficient. Moreover, these changes are enhanced near the Pr-induced metal-insulator transition. Light also causes a contraction of the c-axis in YBa2Cu3Ox which is correlated with the observed photoinduced resistivity changes. These changes are similar to those observed when oxygen-deficient YBa 2Cu3Ox is enriched with oxygen or annealed at room temperature after quenching from high temperatures. | ||||
| Address | Laboratorium voor Vaste Stof-Fysika en Magnetisme, Katholieke Universiteit Leuven, Celestijnenlaan 200 D, B-3001 Leuven, Belgium | ||||
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| ISSN | 00036951 (ISSN) | ISBN | Medium | ||
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| Notes | Cited By (since 1996): 37; Export Date: 17 April 2009; Source: Scopus; doi: 10.1063/1.111078; Language of Original Document: English; Correspondence Address: Lederman, D.; Physics Department; University of California-San Diego San Diego, CA 92093-0319, United States | Approved | no | ||
| Call Number | BT @ osquigui @ | Serial | 390 | ||
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| Author | Watt | ||||
| Title | Photoinduced changes in Raman spectra of YBa2Cu3O6.4 films | Type | Journal Article | ||
| Year |
1994 | Publication | Journal of Superconductivity | Abbreviated Journal | J Supercond |
| Volume | 7 | Issue | 1 | Pages | 131-136 |
| Keywords | Electronic Raman scattering; oxygen ordering; photoinduced superconductivity; two-magnon scattering; Copper oxides; Radiation effects; Raman spectroscopy; Superconducting films; Superconductivity; Oxide superconductors; Photoinduced effects; Yttrium barium cuprates; High temperature superconductors | ||||
| Abstract | The evolution of Raman spectra with illumination has been studied in YBa2Cu3O6.4 films at temperatures between 5-300 K. Low laser power has always been used to avoid local overheating, which was controlled by measuring the local temperature by the Stokes/anti-Stokes ratio. Three important photoinduced effects have been found: (i) the enhancement of the intensity of the observed phonon modes: (Cu(2) at 141 cm-1, O(2)-O(3) at 338 cm-1, and O(4) at 488 cm-1), which may be related to the ordering of oxygen vacancies, (ii) the increase of the electronic scattering background for low Raman frequencies ?, which is in agreement with the enhancement of the static conductivity ?(??0) after illumination, and (iii) the suppression of the intensity of the two-magnon band, which may be caused by the increase of charge carriers due to photodoping. | ||||
| Address | Laboratorium voor Vaste Stof-Fysika en Magnetisme, KU Leuven, Leuven, B-3001, Belgium | ||||
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| Publisher | Kluwer Academic Publishers-Plenum Publishers | Place of Publication | Editor | ||
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| ISSN | 08961107 (ISSN) | ISBN | Medium | ||
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| Notes | Cited By (since 1996): 11; Export Date: 17 April 2009; Source: Scopus; CODEN: JOUSE; doi: 10.1007/BF00730383; Language of Original Document: English; Correspondence Address: Watt | Approved | no | ||
| Call Number | BT @ osquigui @ | Serial | 396 | ||
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