Possible Coexistence of Superconductivity and Magnetism in Intermetallic NiBi3

Abstract

NiBi3 polycrystals were synthesized via a solid state method. X-ray diffraction analysis shows that the main phase present in the sample corresponds to NiBi3 in a weight fraction of 96.82 % according to the refinement of the crystalline structure. SEM - EDS and XPS analysis reveal a homogeneous composition of NiBi3, without Ni traces. The powder superconducting samples were studied by performing magnetic measurements. The superconducting transition temperature and critical magnetic fields were determinated as Tc = 4.05 K, Hc1 = 110 Oe and Hc2 = 3,620 Oe. The superconducting parameters were GL coherence length= 301.5 A, Ginzburg Landau Penetration depth= 1549 A, and k = 5.136. Isothermal measurements below the transition temperature show an anomalous behavior. Above the superconducting transition the compound presents ferromagnetic characteristics up to 750 K, well above the Ni Curie temperature. PACS numbers: Intermetallic Alloys; Superconductivity; Ferromagnetism;