Recently, we have found that the electronic state of Ce₂Ni₃Ge₅ can be tuned by pressure.  For temperatures less than 260 mK (0.26 K),  Ce₂Ni₃Ge₅ transforms into a new stable superconducting phase around acritical pressure Pc = 3.9 GPa.

Ce₂Ni₃Ge₅ crystallizes in the orthorhombic crystal structure with the space group Ibam (#72).   One of the interesting features of this compound is that its crystal structure is closely related to the CeNi₂Ge₂ system.  Recently, we have been successful in growing the single crystal of this compound by flux method  for the first  time  and  studied the anisotropic physical properties.  The  two antiferromagnetic ordering temperatures T_N1 = 5.0 K and T_N2 = 4.3 K have been confirmed on the single crystalline samples.  The figure on the right hand side shows the as grown single crystals. 

Furthermore, we have studied the electrical resistivity of a high quality polycrystalline sample and found that the electronic state of this compound is tuned by pressure and superconductivity is observed at 0.26 K for pressures greater than 3.9 GPa.  The figure on the left hand side shows the temperature dependence of the electrical resistivity for various applied pressures.  The inset clearly shows the supercondcuting onset at 0.26 K. 

References:

1.  A. Thamizhavel, H. Nakashima, Y. Obiraki et al., J. Phys. Soc. Japan (2005) in press

2.  M. Nakashima, H. Kohara, A. Thamizhavel et al., J. Phys.: Condens matter 17 (2005) 4539-4546.