TY - JOUR
T1 - Instability of the Critical State in NdBa2Cu3O7-δ Single Crystals
AU - Koblischka, Michael R.
AU - Murakami, Masato
AU - Koishikawa, Satoru
AU - Johansen, Tom Henning
AU - Baziljevich, Michael
AU - Frello, Thomas
AU - Wolf, Thomas
PY - 1999
Y1 - 1999
N2 - Instabilities of the critical state are observed in various NdBa2Cu3O7-δ 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, we 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 Ha ∥ c and Ha ⊥ c. As a result, we find turbulence not only in a narrow window of temperatures (65 ≤ T ≤ 80 K), but also in a window of applied negative fields ranging between 30 and 80 mT.
AB - Instabilities of the critical state are observed in various NdBa2Cu3O7-δ 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, we 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 Ha ∥ c and Ha ⊥ c. As a result, we find turbulence not only in a narrow window of temperatures (65 ≤ T ≤ 80 K), but also in a window of applied negative fields ranging between 30 and 80 mT.
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U2 - 10.1023/a:1022518406132
DO - 10.1023/a:1022518406132
M3 - Article
AN - SCOPUS:0033314468
VL - 117
SP - 1483
EP - 1487
JO - Journal of Low Temperature Physics
JF - Journal of Low Temperature Physics
SN - 0022-2291
IS - 5-6
ER -