We have succeeded in growing single crystals of the heavy-fermion superconductor CeCo(In1-xZnx)5 with x<=0.07. Measurements of specific heat, electrical resistivity, dc magnetization and ac susceptibility revealed that the superconducting (SC) transition temperature Tc decreases from 2.25 K (x=0) to 1.8 K (x=0.05) by doping Zn into CeCoIn5. Furthermore, these measurements indicate a development of a new ordered phase below T_o ~ 2.2 K for x=>0.05, characterized by the reduced magnetization and electrical resistivity in the ordered phase, and the enhancement of specific heat at T_o. This phase transition can be also recognized by the shoulder-like anomaly seen at H_o ~ 55 kOe in the field variations of the magnetization at low temperatures, which is clearly distinguished from the superconducting critical fields Hc2=49 kOe for x=0.05 and 42 kOe for x=0.07. We suggest from these results that the antiferromagnetic (AFM) order is generated by doping Zn, and the interplay between the SC and AFM orders is realized in CeCo(In1-xZnx)5.
@article{arxiv.1402.0617,
title = {Possible Evolution of Antiferromagnetism in Zn-Doped Heavy-Fermion Superconductor CeCoIn5},
author = {Makoto Yokoyama and Kenji Fujimura and Sara Ishikawa and Masashi Kimura and Takeshi Hasegawa and Ikuto Kawasaki and Kenichi Tenya and Yohei Kono and Toshiro Sakakibara},
journal= {arXiv preprint arXiv:1402.0617},
year = {2014}
}
Comments
5 pages, 3 figures, to appear in J. Phys. Soc. Jpn