Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Publisher: search.filters.publisher.Institute of Electrical and Electronics Engineers Inc.Subject: search.filters.subject.Crystal structure

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  • Conference Object
    Citation - WoS: 36
    Citation - Scopus: 40
    Thermal Management in Large Bi2212 Mesas Used for Terahertz Sources
    (Institute of Electrical and Electronics Engineers Inc., 2009) Kurter, Cihan; Gray, Kenneth E.; Zasadzinski, John F.; Özyüzer, Lütfi; Koshelev, A. E.; Li, Q.; Yamamoto, T.; Kadowaki, K.; Kwok, W. K.; Tachiki, M.; Welp, U.
    We present a thermal analysis of a patterned mesa on a Bi 2Sr2CaCu2O8 (Bi2212) single crystal that is based on tunneling characteristics of the c-axis stack of ∼800 intrinsic Josephson junctions in the mesa. Despite the large mesa volume (e.g., 40 × 300 × 1.2 μm3) and power dissipation that result in self-heating and backbending of the current-voltage curve (I-V), there are accessible bias conditions for which significant polarized THz-wave emission can be observed. We estimate the mesa temperature by equating the quasiparticle resistance, Rqp(T), to the ratio V/I over the entire I-V including the backbending region. These temperatures are used to predict the unpolarized black-body radiation reaching our bolometer and there is substantial agreement over the entire I-V. As such, backbending results from the particular R qp (T) for Bi2212, as first discussed by Fenton, rather than a significant suppression of the energy gap. This model also correctly predicts the observed disappearance of backbending above ∼60 K.
  • Conference Object
    Citation - WoS: 3
    Citation - Scopus: 3
    Low-Field Behavior of Ti-Added Mgb2/Cu Superconducting Wires
    (Institute of Electrical and Electronics Engineers Inc., 2005) Gençer, Ali; Kılıç, Ahmet; Okur, Salih; Güçlü, Nusret; Özyüzer, Lütfi; Belenli, İbrahim
    We report on low-field magnetic properties of Ti-added (0-20 wt.% of Ti) Cu-clad MgB2 superconducting wires. Wires were produced by mixing appropriate amount of Ti and reacted MgB2 powder which was then placed inside Cu tubes with a diameter of 6 mm. The tubes were then cold worked by rolling or drawing to smaller diameters and then annealed at various temperatures to enhance the grain connectivity. XRD studies show that Ti addition results in new but minor phases. We have then measured ac susceptibilities in the temperature range between 20 K and 40 K in ac fields of 20-1600 A/m. The data show that an additional loss mechanism is established with Ti-addition. The calculated ac losses are increasing with increasing Ti-content in the main superconducting matrix.