TY - JOUR
T1 - Fluxon dynamics in Li–Al codoped MgB2 by microwave surface resistance measurements
AU - Li Vigni, Maria
AU - Agliolo Gallitto, Aurelio
AU - Monni, null
AU - Bonura, Marco
PY - 2010
Y1 - 2010
N2 - The magnetic-field-induced variations of the microwave surface resistance, Rs, have been investigated in ceramic Mg_(1-x)(LiAl)_xB_2, with x in the range 0.1 - 0.4. The measurements have been performed on increasing and decreasing the DC magnetic field, H0, at fixed temperatures. At low temperatures, we have observed a magnetic hysteresis in the Rs(H0) curves in all the investigated samples. On increasing the temperature, the range of H0 in which the hysteretic behavior is visible shrinks; however, in the sample with x=0.1 it is present up to temperatures close to Tc. We show that the field dependence of Rs can be quantitatively justified taking into account the critical-state effects on the fluxon lattice only in the sample with x = 0.4. On the contrary, in the samples with x < 0.4 the hysteresis exhibits an unusual shape,similar to that observed in others two-gap MgB_2 samples, which cannot be justified in the framework of the critical-state models.
AB - The magnetic-field-induced variations of the microwave surface resistance, Rs, have been investigated in ceramic Mg_(1-x)(LiAl)_xB_2, with x in the range 0.1 - 0.4. The measurements have been performed on increasing and decreasing the DC magnetic field, H0, at fixed temperatures. At low temperatures, we have observed a magnetic hysteresis in the Rs(H0) curves in all the investigated samples. On increasing the temperature, the range of H0 in which the hysteretic behavior is visible shrinks; however, in the sample with x=0.1 it is present up to temperatures close to Tc. We show that the field dependence of Rs can be quantitatively justified taking into account the critical-state effects on the fluxon lattice only in the sample with x = 0.4. On the contrary, in the samples with x < 0.4 the hysteresis exhibits an unusual shape,similar to that observed in others two-gap MgB_2 samples, which cannot be justified in the framework of the critical-state models.
KW - Fluxon dynamics
KW - MgB2 superconductor
KW - Microwave surface resistance
KW - Fluxon dynamics
KW - MgB2 superconductor
KW - Microwave surface resistance
UR - http://hdl.handle.net/10447/53682
UR - http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6TVJ-4YF5R77-4&_user=519924&_coverDate=10%2F01%2F2010&_rdoc=1&_fmt=high&_orig=gateway&_origin=gateway&_sort=d&_docanchor=&view=c&_acct=C000025965&_version=1&_urlVersion=0&_userid=519924&md5=9b965635accf424b73e3ca4da77046c7&searchtype=a
M3 - Article
VL - 470
SP - 907
EP - 910
JO - Physica C: Superconductivity and its Applications
JF - Physica C: Superconductivity and its Applications
SN - 0921-4534
ER -