[Zurück]

H. Michor, F. Failamani, A. Grytsiv, G. Giester, H. Müller, E. Bauer, P. Rogl:
"Ferromagnetic Kondo lattice behaviour of CeZn(Zn0.29Si0.71)2";
Vortrag: ICM 2015, 20th International Conference onMagnetism, Barcelona, Spain; 05.07.2015 - 10.07.2015.

We report on the ferromagnetic Kondo lattice behavior of novel CeZn(Zn
0.29Si0.71)2, which was studied by means of ac and dc magnetic susceptibility, specific heat and resistivity measurements on flux-‐
grown single crystals as well as on sintered bulk samples. The orthorhombic CeNiSi2-­‐type phase CeZn(Zn0.29Si0.71)2 [space group Cmcm, a=0.42079(1), b=1.765218(3), c=0.41619(1) nm] was identified in the course of an investigation of the phase equilibria in the Ce-­‐Zn
-­‐Si system (<33.3 at.% Ce) in Ref. [1]. Field dependent isothermal well as temperature dependent magnetisation measurements reveal ferromagnetic ordering of CeZn(Zn0.29Si0.71)2 below about Tc=4.4 K with a magnetically ordered moment near 1 μB/Ce at 1.9 K and 6 T. The corresponding specific heat anomaly at 4.4 K displays a significantly reduced magnitude as compared to the value expected from a basic local moment mean-­‐field approach and is analysed in terms of a simple model for a ferromagnetic Kondo lattice system based on the resonant level model by Schotte and Schotte [2], thus, yielding parameters for the ferromagnetic exchange coupling J=14.6 K and the Kondo temperature TK=5 K. The effective paramagnetic moment of Ce, μeff = 2.5 μB, obtained from a Curie--. Weiss fit suggest that the
ground state of Ce-­‐ions in this compound is close to 3+.