Structural, electrical, magnetic and low-temperature specific heat studies of PrPb 2

Abstract

Investigations of the structure, the electrical resistivity, the magnetic properties and the low-temperature specific heat of PrPb 2 have been made. The crystal structure identified by X-ray diffraction for PrPb 2 is the body-centered tetragonal MoSi 2-type structure with a=3.305 Å and c=16.060 Å. The magnetic part of the electrical resistivity for PrPb 2 shows a −log T dependence similarly to that of CePb 2, but its temperature region is not as wide as that of CePb 2. The temperature derivative of the low-temperature magnetic electrical resistivity d ρ mag/d T and the magnetic susceptibility show a broad peak around 6 K. The magnetic susceptibility exhibits Curie–Weiss behavior at high temperatures, and the effective magnetic moment is 3.68 μ B/Pr-mol and practically equals the value of the free trivalent Pr 3+ ion. A linear extrapolation in zero field of the C/ T versus T 2 plot for low-temperature specific heat gives a large electronic specific heat coefficient γ of 656 mJ·mol −1·K −2. Such a large value may be attribute to a Schottky specific heat. The peak around 4.5 K is too small and too broad, compared with a peak representative of a magnetic phase transition. Furthermore, this peak is apparently reduced by applied magnetic fields. Therefore, the peaks observed in the magnetic susceptibility and the specific heat are not correlated with the Néel temperature.