Limits on spin-charge separation from h/2e fluxoids in very underdoped YBa2Cu3O(6+x).
Magnetic flux in superconductors is usually quantized in units of h/2e. Here we report scanning SQUID and scanning Hall probe studies of single fluxoids in high purity YBa2Cu3O6.35 crystals (T(c) less, similar 13 K), extending flux quantization studies to a region of the cuprate phase diagram where the superfluid density is sufficiently low that novel behavior has been predicted. Some scenarios in which superconductivity results from spin-charge separation predict h/e fluxoids in materials with low superfluid density. Our observations of only h/2e fluxoids set limits on these theories.
Wynn
J C
JC
Geballe Laboratory for Advanced Materials, Stanford University, Stanford, California 94305, USA.
Bonn
D A
DA
Gardner
B W
BW
Lin
Y J
YJ
Liang
R
R
Hardy
W N
WN
Kirtley
J R
JR
Moler
K A
KA