Dilution effects on the antiferromagnetic Kondo semiconductor CeOs2Al10

Abstract

We have studied the effects of dilution of Ce sublattice on the unusual antiferromagnetic (AFM) order in the Kondo semiconductor CeOs2Al10 at 28.5 K by the magnetic, transport and specific-heat measurements of single crystals of Ce1-zLazOs2Al10. The effective magnetic moment and paramagnetic Curie temperature hardly change with z up to 0.5, indicating that the 4f state remains unchanged at high temperatures. The suppression of the Néel temperature TN is much weaker than that in 5d hole doped system, Ce(Os1-yRey)2Al10. Therefore, the AFM interaction is robust against the violation of the coherent Ce sublattice. The activation energy in the resistivity decreases in parallel with TN, confirming the argument that the presence of the c-f hybridization gap is a requisite for the unusual AFM order in this system.