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arXiv · 1207.1164

Universality and Critical Behavior at the Critical-End-Point on Itinerant-Metamagnet UCoAl

K. Karube·T. Hattori·S. Kitagawa·K. Ishida·N. Kimura·T. Komatsubara
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Abstract

We performed nuclear-magnetic-resonance (NMR) measurements on itinerant-electron metamagnet UCoAl in order to investigate the critical behavior of the magnetism near a metamagnetic (MM) critical endpoint (CEP). We derived c-axis magnetization $M_c$ and its fluctuation $S_c$ from the measurements of Knight shift and nuclear spin-lattice relaxation rate $1/T_1$ as a function of the c-axis external field ($H_c$) and temperature ($T$). We developed contour plots of $M_c$ and $S_c$ on the $H_c$ - $T$ phase diagram, and observed the strong divergence of $S_c$ at the CEP. The critical exponents of $M_c$ and $S_c$ near the CEP are estimated, and found to be close to the universal properties of a three-dimensional (3-D) Ising model. We indicate that the critical phenomena at the itinerant-electron MM CEP in UCoAl have a common feature as a gas-liquid transition.

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K. Karube, T. Hattori, S. Kitagawa, K. Ishida, N. Kimura, T. Komatsubara. 2012-07-05. Universality and Critical Behavior at the Critical-End-Point on Itinerant-Metamagnet UCoAl. https://doi.org/10.1103/physrevb.86.024428

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