Research output: Contribution to journal › Article › peer-review
Superconductivity in a Ga-Ag nanocomposite with dendritic morphology. / Shevchenko, E.V. ; Charnaya, E.V. ; Lee, M. K.; Chang, L.-J.; Likholetova, M.V. ; Lezova, I.E. ; Kumzerov, Y.A. ; Fokin, A.V. .
In: Physica C: Superconductivity and its Applications, Vol. 574, 1353666, 15.07.2020.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - Superconductivity in a Ga-Ag nanocomposite with dendritic morphology
AU - Shevchenko, E.V.
AU - Charnaya, E.V.
AU - Lee, M. K.
AU - Chang, L.-J.
AU - Likholetova, M.V.
AU - Lezova, I.E.
AU - Kumzerov, Y.A.
AU - Fokin, A.V.
N1 - Funding Information: The present study was supported by RFBR (Russia), grant 19-07-00028, and by MOST (Taiwan)- RFBR (Russia), grant 19-57-52001.
PY - 2020/7/15
Y1 - 2020/7/15
N2 - Dc and ac magnetizations were measured for the 3D nanocomposite consisted of Ga-Ag dendritic grains embedded into a porous glass template with the aim to study the impact of the particular morphology on superconductivity. The temperature range of measurements was from 1.8 to 10 K. The Ga-Ag alloy composition corresponded to the eutectic point (97 at.% Ga, 3 at.% Ag). The nanocomposite behaved as a dirty type-II superconductor with strong pinning, transition temperature near 7.03 K, and enhanced upper critical field. We found a phase diagram with the positive curvature of the upper critical field line at low magnetic fields and a crossover to the negative curvature that correlated to the bend on the field dependence of the vortex potential barriers. We suggested that both the curvature crossover and bend on the field dependence of potential barriers evidenced a vortex structure transformation associated with destroying intergrain links. Other changes in the vortex structure appeared as steps on the dc FC curves and hysteresis between the FC magnetizations obtained upon cooling (FCC) and warming (FCW). These phenomena were not found in the earlier studies of nanocomposites with inclusions of pure Ga and Sn and might be related to the strong heterogeneity of the confined Ga-Ag eutectic alloy.
AB - Dc and ac magnetizations were measured for the 3D nanocomposite consisted of Ga-Ag dendritic grains embedded into a porous glass template with the aim to study the impact of the particular morphology on superconductivity. The temperature range of measurements was from 1.8 to 10 K. The Ga-Ag alloy composition corresponded to the eutectic point (97 at.% Ga, 3 at.% Ag). The nanocomposite behaved as a dirty type-II superconductor with strong pinning, transition temperature near 7.03 K, and enhanced upper critical field. We found a phase diagram with the positive curvature of the upper critical field line at low magnetic fields and a crossover to the negative curvature that correlated to the bend on the field dependence of the vortex potential barriers. We suggested that both the curvature crossover and bend on the field dependence of potential barriers evidenced a vortex structure transformation associated with destroying intergrain links. Other changes in the vortex structure appeared as steps on the dc FC curves and hysteresis between the FC magnetizations obtained upon cooling (FCC) and warming (FCW). These phenomena were not found in the earlier studies of nanocomposites with inclusions of pure Ga and Sn and might be related to the strong heterogeneity of the confined Ga-Ag eutectic alloy.
KW - TEMPERATURE
KW - GALLIUM
KW - SUSCEPTIBILITY
KW - IRREVERSIBILITY
KW - TRANSITION
KW - MOTION
UR - http://www.scopus.com/inward/record.url?scp=85084558414&partnerID=8YFLogxK
UR - https://www.mendeley.com/catalogue/4e21b17c-83c0-3541-be0f-145da484fc17/
U2 - 10.1016/j.physc.2020.1353666
DO - 10.1016/j.physc.2020.1353666
M3 - Article
VL - 574
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
M1 - 1353666
ER -
ID: 71137987