  The temperature dependence of the anisotropy of the superconducting state
parameters, {\gamma}, was studied by torque magnetometry for the high
temperature superconductor SmBa2Cu3Ox in magnetic fields of up to 9 T. The
measurements were performed on four underdoped single crystals with oxygen
contents corresponding to Tc's varying from 42.8 to 63.6 K. The anisotropy was
found to be strongly temperature dependent, while only a weak dependence on the
magnetic field was observed. No evidence for a field dependent superfluid
density was found. Possible origins of the temperature dependence of the
anisotropy are discussed.
