  The anisotropic physical properties of single crystals of orthorhombic PtSn4
are reported for magnetic fields up to 140 kOe, applied parallel and
perpendicular to the crystallographic b-axis. The magnetic susceptibility has
an approximately temperature independent behavior and reveals an anisotropy
between ac-plane and b-axis. Clear de Haas-van Alphen oscillations in fields as
low as 5 kOe and at temperatures as high as 30 K were detected in magnetization
isotherms. The thermoelectric power and resistivity of PtSn4 show the strong
temperature and magnetic field dependencies. A change of the thermoelectric
power at H = 140 kOe is observed as high as ~ 50 mu-V/K. Single crystals of
PtSn4 exhibit very large transverse magnetoresistance of ~ 5x10^5% for the
ac-plane and of ~ 1.4x10^5% for the b-axis resistivity at 1.8 K and 140 kOe, as
well as pronounced Shubnikov-de Haas oscillations. The magnetoresistance of
PtSn4 appears to obey Kohler's rule in the temperature and field range
measured. The Hall resistivity shows a linear temperature dependence at high
temperatures followed by a sign reversal around 25 K which is consistent with
thermoelectric power measurements. The observed quantum oscillations and band
structure calculations indicate that PtSn4 has three dimensional Fermi
surfaces.
