Ferromagnetic Quantum Critical Point Induced by Tuning the Magnetic Dimensionality of the Heavy-Fermion Iron Oxypnictide Ce(Ru1-xFex)PO

• Published in: Journal of the Physical Society of Japan 2013-03, Vol.82 (3), p.033704-033704-4
• Main Authors: Kitagawa, Shunsaku, Ishida, Kenji, Nakamura, Tetsuro, Matoba, Masanori, Kamihara, Yoichi
• Format: Article
• Language: English
• ISSN: 0031-9015; 1347-4073
• DOI: 10.7566/JPSJ.82.033704

We have performed 31 P-NMR measurements of the $c$-axis-aligned poly-crystal Ce(Ru 1-x Fe x )PO with a two-dimensional layered structure in order to understand the origin of $T_{\text{Curie}}$ suppression by Fe substitution. The variation in the magnetic-fluctuation character with respect to $x$ is investigated from the in-plane and out-of-plane fluctuations and the relationship between the static spin susceptibility and the in-plane fluctuation. It was found that three-dimensional ferromagnetic (FM) correlations are dominant and give rise to the FM ordering in CeRuPO. The out-of plane fluctuations are significantly suppressed with increasing $x$, and it was revealed that the FM fluctuations become two dimensional near a FM quantum critical point (QCP). Our NMR results strongly suggest that a unique FM QCP in Ce(Ru 1-x Fe x )PO is induced by the suppression of the magnetic correlations along the $c$-axis, which is a different mechanism from that presumed in heavy-fermion compounds.