Strong Longitudinal Magnetic Fluctuations Near Critical End Point in UCoAl : A ^<59>Co-NMR Study
Strong Longitudinal Magnetic Fluctuations Near Critical End Point in UCoAl : A ^<59>Co-NMR Study
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UCoAl 中临界终点附近的强纵向磁涨落：^<59>Co-NMR 研究
DOI：
10.1143/jpsj.80.093707
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发表时间：
2011
影响因子：
1.7
通讯作者：
et al
中科院分区：
文献类型：
--
作者：
H.Nohara;H.Kotegawa;et al
我们报告了UCoAl中的59 Co-NMR测量结果，其中由于磁场增强铁磁性而发生变磁性。从顺磁（PM）态到铁磁态的变磁相变在低温下是一级相变，而在高温下当TCEP = 12 K时，变磁相变在临界终点（CEP）处转变为一级相变。弛豫速率1/T1和1/T2的对比表明，U磁矩的纵向磁起伏被强烈增强，尤其是在CEP附近。即使在不发生磁跃迁的PM状态下，也可以确认CEP波动的广泛扩散。
We report59Co-NMR measurements in UCoAl where metamagnetism occurs owing to the enhancement of ferromagnetism by a magnetic field. The metamagnetic transition from a paramagnetic (PM) state to a ferromagnetic state is a first-order transition at low temperatures, but it changes to a crossover at high temperatures on crossing the critical end point (CEP) atTCEP∼12 K. The contrasting behavior between the relaxation rates 1/T1and 1/T2suggests that the longitudinal magnetic fluctuation of the U moments is strongly enhanced, especially near the CEP. A wide diffusion of the fluctuation from the CEP can be confirmed even in the PM state where the magnetic transition does not occur.