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arXiv · 1502.05155

Ferromagnetic Critical Behavior in U(Co$_{1-x}$Fe$_x$)Al ($0 \leq x \leq 0.02$) Studied by $^{59}$Co Nuclear Quadrupole Resonance Measurement

Kosuke Karube·Taisuke Hattori·Kenji Ishida·Noriaki Kimura
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Abstract

In order to investigate physical properties around a ferromagnetic (FM) quantum transition point and a tricritical point (TCP) in the itinerant-electron metamagnetic compound UCoAl, we have performed the $^{59}$Co nuclear quadrupole resonance (NQR) measurement for the Fe-substituted U(Co$_{1-x}$Fe$_x$)Al ($x$ = 0, 0.5, 1, and 2%) in zero external magnetic field. The Fe concentration dependence of $^{59}$Co-NQR spectra at low temperatures indicates that the first-order FM transition occurs at least above $x$ = 1%. The magnetic fluctuations along the $c$ axis detected by the nuclear spin-spin relaxation rate $1/T_2$ exhibit an anomaly at $T_\mathrm{max}$ $\sim$ 20 K and enhance with increasing $x$. These results are in good agreement with theoretical predictions and indicate the presence of prominent critical fluctuations at the TCP in this system.

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Kosuke Karube, Taisuke Hattori, Kenji Ishida, Noriaki Kimura. 2015-02-18. Ferromagnetic Critical Behavior in U(Co$_{1-x}$Fe$_x$)Al ($0 \leq x \leq 0.02$) Studied by $^{59}$Co Nuclear Quadrupole Resonance Measurement. https://doi.org/10.1103/physrevb.91.075131

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