  Thermal expansion, electrical resistivity, magnetization, and specific heat
measurements were performed on URu$_{2-x}$Fe$_{x}$Si$_{2}$ single crystals for
various values of the Fe concentration $x$ in both the hidden order (HO) and
large moment antiferromagnetic (LMAFM) regions of the phase diagram. Our
results show that the paramagnetic (PM) to HO and LMAFM phase transitions are
manifested differently in the thermal expansion coefficient. For Fe
concentrations near the boundary between the HO and LMAFM phases at $x_c$ ~
0.1, we observe two features in the thermal expansion upon cooling, one that
appears to be associated with the transition from the PM to the HO phase and
another one at lower temperature that may be due to the transition from the HO
to the LMAFM phase. These two features have not been observed in other
measurements such as specific heat or neutron scattering. In addition, the
uniaxial pressure derivative of the transition temperature, based on a
calculation using thermal expansion and specific heat data, changes
dramatically when crossing from the HO to the LMAFM phase.
