Large anisotropy in magnetic field induced superconductors λ-(BETS)2FexGa1-xCl4

Resistance measurements have been performed to investigate the field induced superconductivity in λ-(BETS)2FexGa1-xCl4 (x=0.47). In magnetic fields parallel to the conduction layers (c-axis), the superconducting (S) phase is induced between 5 and 24 T at 1.6 K. However, when the field is tilted from the c-axis to the b*-axis (normal to the conduction layers), the S phase disappears at around 6 deg. . This strong anisotropic behavior shows that the orbital effect plays a significant role in the destructive mechanism of the superconductivity. The orbital critical field normal to the conduction layers is estimated to be 1.5 T at 1.6 K