  Whereas resistivity and ac susceptibility measurements on the magnetic (Tm ~
130 K) superconductor (Tc,onset ~ 50 K) RuSr2GdCu2O8 (Ru-1212Gd) reported by
different research groups reveal a universal behavior in its superconducting
state, this is not the case with the superconducting quantum interference
device (SQUID) magnetization measurements. The reported SQUID measurements in
the superconducting state of Ru-1212Gd reveal a variety of behaviors, leaving
the question of bulk superconductivity for this compound open. We review
several of the reported behaviors by presenting measurements done on our
samples belonging to the same batch. Based on the observed sensitivity of
Ru-1212Gd to magnetic field inhomogeneities when it is moved in the
superconducting magnet of the SQUID magnetometer during the measurements, we
suggest that the reported different behaviors can be the result of different
field profiles in the superconducting magnet and not of different
superconducting properties. In order to avoid the artifacts arising from moving
the sample in an inhomogeneous field, we did measurements on a stationary
Ru-1212Gd sample employing a home made SQUID magnetometer. The measured curves
showed none of the suspicious ``symptoms'' present in the curves measured with
a magnetometer employing sample movement (e.g. no reversal of the features
observed in the superconducting state of Ru-1212Gd by a field reversal) and if
verified by measurements on stationary samples by other groups a universal
behavior in the superconducting state of Ru-1212Gd can be revealed by the SQUID
measurements too. Our considerations support the existence of bulk
superconductivity for Ru-1212Gd.
