Evidence for static magnetism in the vortex cores of ortho-II YBa2Cu3O6.50.
Evidence for static alternating magnetic fields in the vortex cores of underdoped YBa2Cu3O6+x is reported. Muon spin rotation measurements of the internal magnetic field distribution of the vortex state of YBa2Cu3O6.50 in applied fields of H = 1 T and H = 4 T reveal a feature in the high-field tail of the field distribution which is not present in optimally doped YBa2Cu3O6.95 and which fits well to a model with static magnetic fields in the vortex cores. The magnitude of the fields is estimated to be 18(2) G and decreases above T = 10 K. We discuss possible origins of the additional vortex core magnetism within the context of existing theories.
Miller
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Department of Physics & Astronomy, University of British Columbia, Vancouver, Canada. miller@physics.ubc.ca
Kiefl
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Brewer
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Sonier
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Chakhalian
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Dunsiger
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Morris
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Price
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Bonn
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Liang
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