Thursday, October 18, 2012

1210.4604 (Shunsaku Kitagawa et al.)

Ferromagnetic Quantum Critical Point in Heavy-Fermion Iron Oxypnictide
Ce(Ru$_{1-x}$Fe$_x$)PO
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Shunsaku Kitagawa, Kenji Ishida, Tetsuro Nakamura, Masanori. Matoba, annd Yoichi Kamihara
We have performed ^{31}P-NMR measurements on Ce(Ru_{1-x}Fe_{x})PO in order to investigate ferromagnetic (FM) quantum criticality, since heavy-fermion (HF) ferromagnet CeRuPO with a two-dimensional structure turns to a HF paramagnet by an isovalent Fe-substitution for Ru. We found that Ce(Ru_{0.15}Fe_{0.85})PO shows critical fluctuations down to \sim 0.3 K, as well as the continuous suppression of Curie temperature and the ordered moments by the Fe-substitution. These experimental results suggest the presence of a FM quantum critical point (QCP) at x \sim 0.86, which is a rare example among itinerant ferromagnets. In addition, we point out that the critical behaviors in Ce(Ru_{0.15}Fe_{0.85})PO share the similarity with those in YbRh_{2}Si_{2}, where the local criticality of $f$ electrons has been discussed. We reveal that Ce(Ru_{1-x}Fe_{x})PO is a new system to study FM quantum criticality in HF compounds.
View original: http://arxiv.org/abs/1210.4604

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