TY - GEN
T1 - New phase line in the mixed state of Nb/NbZr multilayers
AU - Nojima, Tsutomu
AU - Masuda, Taisuke
AU - Nakano, Shigeru
AU - Kuwasawa, Yoshinori
PY - 1994
Y1 - 1994
N2 - The superconducting multilayer Nb/NbZr is known to show an upturn feature in the parallel upper critical field Hc2|(T) at a characteristic temperature T+ with decreasing T. This phenomenon occurs due to the change of the position for nucleation of order parameter Δ(r) from Nb to NbZr layers. In order to understand the behavior of the localized Δ(r) in the mixed state, we have measured the critical current density J c of Nb/NbZr as a function of H and of angle between H and film plane. In this system, the peak effect has been reported in Jc(H) above T+ by previous work. In this work, besides this peak, two kinds of kink structures in Jc(H) are observed at fields HL1 and HL2 only in the temperatures above T+.HL1(T) and HL2(T) are plotted around the extrapolated line from Hc2|(T) above T+. From the field dependence of the angular derivative of Jc and the discussion about the free energy in the system, we will show the possibility of the phase transition at these characteristic fields.
AB - The superconducting multilayer Nb/NbZr is known to show an upturn feature in the parallel upper critical field Hc2|(T) at a characteristic temperature T+ with decreasing T. This phenomenon occurs due to the change of the position for nucleation of order parameter Δ(r) from Nb to NbZr layers. In order to understand the behavior of the localized Δ(r) in the mixed state, we have measured the critical current density J c of Nb/NbZr as a function of H and of angle between H and film plane. In this system, the peak effect has been reported in Jc(H) above T+ by previous work. In this work, besides this peak, two kinds of kink structures in Jc(H) are observed at fields HL1 and HL2 only in the temperatures above T+.HL1(T) and HL2(T) are plotted around the extrapolated line from Hc2|(T) above T+. From the field dependence of the angular derivative of Jc and the discussion about the free energy in the system, we will show the possibility of the phase transition at these characteristic fields.
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U2 - 10.1117/12.179166
DO - 10.1117/12.179166
M3 - Conference contribution
AN - SCOPUS:0028741132
SN - 0819414522
SN - 9780819414526
T3 - Proceedings of SPIE - The International Society for Optical Engineering
SP - 312
EP - 319
BT - Proceedings of SPIE - The International Society for Optical Engineering
PB - Publ by Society of Photo-Optical Instrumentation Engineers
T2 - Superconducting Superlattices and Multilayers
Y2 - 24 January 1994 through 25 January 1994
ER -