Experimental and theoretical study of CePdBi

In this paper we present experimental results obtained for CePdBi by means of specific heat, electrical resistivity, magnetization and x-ray photoemission spectroscopy (XPS) measurements as well as fully relativistic band structure calculations. CePdBi crystallizes in MgAgAs structure and exhibits a transition to a magnetically ordered state at T-M similar or equal to 2 K, and a subsequent transition to a superconducting state at T-C similar or equal to 1.3 K. The superconducting phase has a significant critical field of about 1.4 T. The x-ray diffraction, resistivity and magnetic susceptibility data show that CePdBi exhibits significant atomic disorder, which is a typical feature of Heusler alloys. It seems that the superconducting transition is caused by part of the disordered phase, which from the Meissner shielding can be estimated to constitute similar to 8% of the sample volume. Due to atomic disorder, CePdBi exhibits metamagnetic behavior below T-M and spin-glass-like features just above T-M. Band structure calculations confirm the magnetic ground state of the CePdBi system and the possibility of formation of a narrow pseudogap near the Fermi level, which can also be seen in resistivity data. The spin-orbit interaction strongly influences the band structure and the shape of the semiconducting gap.