Superconducting layer thickness dependence of magnetic relaxation property in CVD processed YGdBCO coated conductors

Autor: K. Shikimachi, Tomonori Watanabe, Y. Takahashi, Edmund Soji Otabe, Naoji Kashima, Teruo Matsushita, Masaru Kiuchi, Shigeo Nagaya
Rok vydání: 2011
Předmět:
Zdroj: Physica C: Superconductivity and its Applications. 471:1025-1028
ISSN: 0921-4534
Popis: One of the most important properties of coated conductors for Superconducting Magnetic Energy Storage (SMES) is the relaxation property of persistent superconducting current. This property can be quantitatively characterized by the apparent pinning potential U 0 ∗ . In this paper, the dependence of U 0 ∗ on the thickness of superconducting layer d is investigated in the range of 0.33–1.43 μm at the temperature range of 20–30 K and in magnetic fields up to 6.5 T for Y 0.7 Gd 0.3 Ba 2 Cu 3 O 7− δ coated conductors. It was found that the value of critical current density did not appreciably depend on d at 20 K. This indicates that no structural deterioration of superconducting layer occurs during the process of increasing thickness. U 0 ∗ increases and then tends to decrease with an increasing magnetic field. The magnetic field at which U 0 ∗ starts to decrease increases with increasing thickness. This property was analyzed using the flux creep–flow model. Application of scaling law is examined for the dependence of U 0 ∗ on magnetic field and temperature. It was found that the dependence could be expressed using scaling parameters B peak , U 0 peak ∗ in the temperature range 20–30 K.
Databáze: OpenAIRE
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