Autor: Thomas Wolf, Satoru Koishikawa, M. Baziljevich, Masato Murakami, Michael Rudolf Koblischka, Tom H. Johansen, T. Frello
Rok vydání: 1999
Předmět:
Zdroj: Journal of Low Temperature Physics. 117:1483-1487
ISSN: 0022-2291
DOI: 10.1023/a:1022518406132
Popis: Instabilities of the critical state are observed in various NdBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} single crystals by means of direct magneto-optic (MO) imaging while warming up flux states containing vortices of opposite polarity. Using the same samples as in the MO investigations, the authors observe for the first time characteristic steps in the integral magnetization measured by means of a SQUID system, which allows a constant temperature sweep. The integral measurement technique enables the study of the instability phenomenon (turbulence) in a much wider range of temperatures and fields than the MO investigations, and also in the orientations H{sub a} {parallel} c and H{sub a} {perpendicular} c. As a result, they find turbulence not only in a narrow window of temperatures (65 {le} T {le} 80 K), but also in a window of applied negative fields ranging between 30 and 80 mT.
Databáze: OpenAIRE
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