Percolative Superconductivity in Mg1-xB2.
Our results from various transport experiments on Mg1-xB2 indicate a surprising effect associated with the presence of a Mg deficiency in MgB2: the phase separation between Mg-vacancy rich and Mg-vacancy poor phases. The Mg-vacancy poor phase is superconducting, but the insulating nature of the Mg-vacancy rich phase probably originates from the Anderson (disorder-induced) localization of itinerant carriers. Furthermore, electron diffraction measurements indicate that within vacancy-rich regions these defects tend to order with intriguing patterns. This electronic phase separation in Mg1-xB2 shows similar, but also distinct characteristics compared with that observed in La(2)CuO(4+delta).
Sharma
P A
PA
Department of Physics & Astronomy, Rutgers University, Piscataway, New Jersey 08854, USA.
Hur
N
N
Horibe
Y
Y
Chen
C H
CH
Kim
B G
BG
Guha
S
S
Cieplak
Marta Z
MZ
Cheong
S-W
SW