  We report measurements of the time-averaged surface floating potential of
magnetic and non-magnetic spherical probes (or large dust particles) immersed
in a magnetized capacitively coupled discharge. In this study, the size of the
spherical probes is taken greater than the Debye length. The surface potential
of a spherical probe first increases, i.e. becomes more negative at low
magnetic field (B $<$ 0.05 T), attains a maximum value and decreases with
further increase of the magnetic field strength (B $>$ 0.05 T). The rate of
change of the surface potential in the presence of a B-field mainly depends on
the background plasma and types of material of the objects. The results show
that the surface potential of the magnetic sphere is higher (more negative)
compared to the non-magnetic spherical probe. Hence, the smaller magnetic
sphere collects more negative charges on its surface than a bigger non-magnetic
sphere in a magnetized plasma. The different sized spherical probes have nearly
the same surface potential above a threshold magnetic field (B $>$ 0.03 T),
implicating a smaller role of size dependence on the surface potential of
spherical objects. The variation of the surface potential of the spherical
probes is understood on the basis of a modification of the collection currents
to their surface due to charge confinement and cross-field diffusion in the
presence of an external magnetic field.
