Effects of pressure on T$_{c}$ in (Tl$_{0.59}$Cs$_{0.26})$Fe$_{1.9}$Se$_{2}$*

Hydrostatic-pressure (up to 0.96 GPa) dependence of T$_{c}$ in a newly discovered Fe-based superconductor (Tl$_{0.59}$Cs$_{0.26})$Fe$_{1.9}$Se$_{2}$ is reported. The room temperature powder $x$-ray diffraction and crystallographic data provide the evidence for bulk superconductivity with T$_{c}$ around 28 K in a tetragonal ThCr$_{2}$Si$_{2}$-type structure at ambient pressure. Static Magnetization measurements under pressure indicate that the linear increase in T$_{c}$ is initially rapid (dT$_{c}$/dP $=$ 9.9 K GPa$^{-1})$ but slows down to dT$_{c}$/dP $=$ 2.5 K GPa$^{-1}$ for P \textgreater 0.18 GPa. The T$_{c}$ of the superconducting phase is 32 K at pressure P $=$ 0.96 GPa. The simple rigid band model may not be sufficient to account for the observations if the lattice parameters of the unit cell are linearly decreased with the hydrostatic pressure.