The Kunchur group investigates phenomena in superconducting nanowires and thin films, as well as other condensed-matter systems, at ultra-short time scales and under extreme conditions of current density, electric field and dissipation levels. This has led to the discovery or first quantitative confirmation of the following phenomena/regimes: (1) Free flux flow (2) Hot-electron vortex instability (3) Flux fragmentation (4) Vortex explosion (5) Flux-creep based memory effect (6) Current-induced pair breaking in a high-temperature superconductor and (7) Superfluid ballistic acceleration. Publications related to this research can be downloaded from the list below.
Evaluating Superconductors through Current Induced Depairing, M. N. Kunchur, Condens. Matter 4, 54 (2019). pdf file
Dissipative-regime measurements as a tool for confirming and characterizing near-room-temperature superconductivity, C. L. Dean and M. N. Kunchur, review article in Quantum Studies: Mathematics and Foundations 5, 111-121 (2018).
Anomalous oscillatory magnetoresistance in superconductors, M. N. Kunchur, C. L. Dean, and B. I. Ivlev, Phys. Rev. B 94, 054504 (2016).
Current driven vortex-antivortex pair breaking and vortex explosion in the Bi
2Te3/FeTe interfacial superconductor, C. L. Dean, M. N. Kunchur, Q.L. He, H. Liu, J. Wang, R. Lortz, I.K. Sou, Physica C 527, 46 (2016). pdf fileEnergy Losses in Superconductors, C. L. Dean, M. N. Kunchur, J. of Power and Energy Eng. 4, 20 (2016).
Anomalous oscillatory magnetoresistance in superconducting transitions,
M. N. Kunchur, C. L. Dean, and B. I. Ivlev, submitted to Phys. Rev. Lett. (2016).Current induced depairing in the Bi2Te3/FeTe interfacial superconductor, M. N. Kunchur, C. L. Dean, N. Shayesteh Moghadam, J. M. Knight, Q. L. He, H. Liu, J. Wang, R. Lortz, I. K. Sou, and A. Gurevich, Phys. Rev. B 92, 094502 (2015). pdf file
Pinning mechanism in electron-doped HTS Nd2-xCexCuO4-d epitaxial films, A. Guarino, A. Leo, G. Grimaldi, N. Martucciello, C. Dean, M. N. Kunchur, S. Pace and A. Nigro, Supercond. Sci. Technol. 27, 124011 (2014).
Depairing current density of Nd2-xCexCuO4-d superconducting films, M. N.
Kunchur, C. Dean, M. Liang, N. S. Moghaddam, A. Guarino, A. Nigro,G. Grimaldi,
A. Leo, Physica C 495, 66 (2013).
Depairing current density of infinite-layer Sr1-xLaxCuO2 superconducting films,
M. Liang, M. N. Kunchur, L. Fruchter, Z.Z. Li, Physica C 492, 178 (2013).
The Vortex Explosion Transition, M. N. Kunchur, M. Liang, and A. Gurevich, AIP Conf. Proc. 1512, 19 (2013).
Thermally activated dynamics of spontaneous perpendicular vortices tuned by parallel magnetic fields in thin superconducting films, M. N. Kunchur, M. Liang, and A. Gurevich, Phys. Rev. B 86, 024521 (2012). pdf file
Non-Linear and Unstable Flux Vortex Dynamics, M. N. Kunchur, M. Liang, J. Hua, and Z. Xiao, AIP Conf. Proc. 1349, 911 (2011).
Transient response of a superconductor in an applied electric field, M. N. Kunchur and G. F. Saracila, Ch. no. 10, pg. 129 in “Physical Properties of Nanosystems”, NATO Science for Peace and Security Series B: Physics and Biophysics; Bonca, Janez; Kruchinin, Sergei (Eds.); 1st Edition, 2011, IX, 350 p., Hardcover; ISBN: 978-94-007-0043-7 (2011).
Vortex instability in molybdenum-germanium superconducting films, M. Liang and M. N. Kunchur, Phys. Rev. B 82, 144517 (2010). pdf file
Evaluating free flux flow in low-pinning molybdenum-germanium superconducting films, M. Liang, M. N. Kunchur, J. Hua and Z. Xiao, Phys. Rev. B 82, 064502 (2010). pdf file
Ballistic acceleration of a supercurrent in a superconductor, G. F. Saracila and M. N. Kunchur, Phys. Rev. Lett. 102, 077001 (2009). pdf file
Time evolution of a supercurrent during an applied voltage, M. N. Kunchur and G. F. Saracila, Proceedings of the 53rd DAE Solid State Physics Symposium, vol. 53, pg. 907 (2008).
Temporal resolution of hearing probed by bandwidth restriction, M. N. Kunchur, Acta Acustica united with Acustica 94, 594–603 (2008). pdf file
High-field flux dynamics in disordered two-band superconductivity, J. M. Knight and M. N. Kunchur, book chapter no. 7, pg. 71 in "Electron Transport in Nanosystems", Eds. J. Bonca and S. Kruchinin, Springer Publishers (ISBN: 978-1-4020-9144-5), Dordrecht, The Netherlands (2008).
Probing the temporal resolution and bandwidth of human hearing , M. N. Kunchur, Proc. of Meetings on Acoustics (POMA) 2, 050006 (2008). pdf file
Flux flow in a two-band superconductor with delocalized
electric fields, J. M.
Knight and M. N. Kunchur, Phys. Rev. B 77, 024516 (2008).
pdf
file
Audibility of temporal smearing and time misalignment of
acoustic signals, M.
N. Kunchur, Technical Acoustics, 17 (2007).
pdf
file
Energy relaxation at
a hot-electron vortex instability,
J. M. Knight and M. N.
Kunchur, Phys. Rev. B 74, 64512 (2006).
pdf
file
Anomalous flux dynamics in magnesium diboride films, M. N. Kunchur, G. Saracila, D. A. Arcos, Y. Cui, A. Pogrebnyakov, P. Orgiani, X. X. Xi, P. W. Adams, and D. P. Young, Physica C 437-438, 171-175 (2006). pdf file
Suppressed flux motion in magnesium diboride films, D. H. Arcos and M. N. Kunchur, Phys. Rev. B (in press) 2005. pdf file
Current-Induced Pair Breaking in
Magnesium Diboride, M. N. Kunchur,
Topical Review published in the J. Phys.: Condens. Matter 16, R1183-R1204
(2004). pdf
file
The pair-breaking critical current
density of magnesium diboride,
M. N. Kunchur, Sung-Ik Lee, and W. N. Kang, Phys Rev.
B 68, 064516 (2003). pdf
file
Critical flux pinning and enhanced upper-critical-field in magnesium diboride films, M. N. Kunchur, C. Wu, B. I. Ivlev, Sung-Ik Lee, and W. N. Kang, Phys. Rev. B 68, 100503 (2003). pdf file ps file
Mixed-state transport
characteristics of magnesium diboride films, M.
N. Kunchur, C. Wu, D. H. Arcos, G. Saracila, E.-M. Choi, K. H. P. Kim, W. N. Kang,
S.-I. Lee, Braz. J. Phys. 33, 705 (2003). pdf
file ps file
Unstable flux flow due to heated electrons in Y-Ba-Cu-O films, M. N. Kunchur, Phys. Rev. Lett. 89, 137005 (2002). pdf file
Hot-Electron Instability in Superconductors, M. N. Kunchur and J. M. Knight, Mod. Phys. Lett. B 17, 549 (2003). pdf file
Shear fragmentation of unstable flux flow, M. N. Kunchur, B.I. Ivlev, and J. M. Knight, Phys. Rev. B 66, 60505 (2002). pdf file
Steps in the negative-differential-conductivity regime of a superconductor, M. N. Kunchur, B.I. Ivlev, and J. M. Knight, Phys. Rev. Lett. 87, 177001 (2001). pdf file
Van Hove singularities and vortex motion in superconductors, B.I. Ivlev, M. N. Kunchur and S. Mejia Rosales, Phys. Rev. B 64, 024508 (2001). pdf file
Metallic
normal state of YBa2Cu3O7 , M. N.Kunchur, B. I. Ivlev, D. K.
Christen, and J. M. Phillips, Phys. Rev. Lett. 84, 5204 (2000). pdf file
Cherenkov resonances in vortex dissipation in superconductors, B.I. Ivlev, S. Mejia Rosales, and M. N. Kunchur, Phys. Rev. B 60, 12419 (1999). pdf file
Hysteretic Internal Fields and Critical Currents in Polycrystalline Superconductors, M. N. Kunchur and T. R. Askew, J. Appl. Phys. 84, 6763 (1998).pdf file GZipped PS file
Decomposition of the Hall effect in the mixed state of superconductors, M. N. Kunchur, D. K. Christen, and B. I. Ivlev, Physica C 307, 241 (1998).pdf file
High frequency effects in superconductors from short duration dc pulses, M. N. Kunchur, D. K. Christen, and J. M. Phillips, pg. 180 in "Advances in Superconductivity and its Applications to Microwaves", Eds. G. P. Srivasatava and R. P. Tandon, Allied Publishers Ltd., New Delhi (1998).pdf file ps file
Hall effect in YBa2Cu3O7 in the limit of free flux flow, M. N. Kunchur, D. K. Christen, C. E. Klabunde, and J. M. Phillips, Phys. Rev. Lett. 72, 2259 (1994).pdf file
Pair-breaking effect of high current densities on the superconducting transition on YBa2Cu3O7 , M. N.Kunchur, D. K. Christen, C. E. Klabunde, and J. M. Phillips, Phys. Rev. Lett. 72, 752 (1994).pdf file
Observation of free flux flow at high dissipation levels in YBa2Cu3O7 epitaxial films, M. N. Kunchur, D. K. Christen, and J. M. Phillips, Phys. Rev. Lett 70, 998 (1993). pdf file
Exploring the dissipative regime of superconductors for practical current-lead applications, M. N. Kunchur, D. K. Christen, C. E. Klabunde, and K. Salama, Appl. Phys. Lett. 67, 848 (1995).pdf file
Novel transport behavior found in the dissipative
regime of superconductors, M. N.
Kunchur, Mod. Phys. Lett. B. 9,
399 (1995). (Hard copy can be sent by mail upon requrest.)
Transport Behavior in Superconductors at Extreme Dissipation Levels, M. N. Kunchur, D. K. Christen, and B. I. Ivlev, pg. 135 in "Advances in Superconductivity: New Materials, Critical Currents and Devices", Eds. R. Pinto, S. K. Malik, A. K. Grover, and P. Ayyub, New Age International Ltd. Publishers, New Delhi (1997).pdf file
Critical fields and critical currents of superconducting discs in transverse magnetic fields, M.N. Kunchur and S.J. Poon, Phys. Rev. B 43, 2916 (1991).pdf file
Superposition of decaying flux distributions: A memory effect from flux creep, M.N. Kunchur, S.J. Poon, and M.A. Subramanian, Phys. Rev. B 41, 4089 (1990).pdf file
Absence of Superconductivity in Metallic Granular Aluminum, M. Kunchur, P. Lindenfeld, W. L. Mclean, and J. S. Brooks, Phys. Rev. Lett. 59, 1232 (1987).pdf file
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