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Cantilever Magnetometry using a Single Uranium
Crystal.
Brandy Benedict
Faculty Advisor: George Schmiedshoff
We have
determined the lower critical magnetic field values
of a single-crystal of type II superconductor LuNi2B2C
at temperatures between 3K and 11K using cantilever
magnetometry. This compound is part of a class of
rare earth nickel borocarbides, whose properties are
especially unusual in that they can simultaneously
exhibit both superconductivity and magnetism, two
competing states that were not previously known to
coexist.
The lower
critical field values we obtained were much lower
than expected. Our best guess is that the values
for the lower critical field, Hc1, follow
a quadratic dependence on temperature, although
further research is needed to determine this to a
high degree of certainty. This quadratic dependence
indicates that there is some anisotropy between the
single-crystal and polycrystalline forms of LuNi2B2C.
Support provided by:
National
Science Foundation Division of Materials Research
grant |
