Structural control of d-f interaction in the CeFe1−xRuxAsO system
1 Institute for Superconducting and Electronic Materials, University of Wollongong North Wollongong, NSW 2522, Australia
2 Department of Physics, Zhejiang University - Hangzhou 310027, China
Received: 20 June 2012
Accepted: 9 August 2012
The isovalent substitution effect of Ru in CeFe1−xRuxAsO (0 ⩽ x ⩽ 1) has been systematically studied by powder X-ray diffraction, electrical resistivity, magnetization, and specific heat measurements. The antiferromagnetic (AFM) ordering of both d and 4f electrons are suppressed upon Ru doping, followed by Pauli paramagnetism (d electrons) and local moment paramagnetism (4f electrons) with strong ferromagnetic fluctuation, respectively. Neither superconductivity above 2 K nor pronounced Kondo screening are observed in the substitution phase diagram. Combined with published results of the cerium-based quaternary compounds CeMXO(M = Fe, Ru; X = P, As), our data suggest that the end member CeRuAsO is on the verge of becoming an FM Kondo lattice. Meanwhile, the ground state of 4f electrons in the quaternary CeMXO system should be determined by both the interlayer d-f Kondo coupling (JKondo) and the intralayer Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction (JRKKY ), which are both very sensitive to the change in crystal structure.
PACS: 74.70.Xa – Pnictides and chalcogenides / 75.20.Hr – Local moment in compounds and alloys; Kondo effect, valence fluctuations, heavy fermions / 71.20.Eh – Rare earth metals and alloys
© EPLA, 2012