Atomic mobility in liquid gallium under nanoconfinement
Atomic mobility in liquid gallium under nanoconfinement
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纳米约束下液态镓中的原子迁移率
DOI：
10.1103/physrevb.72.035406
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发表时间：
2005
影响因子：
3.7
通讯作者：
Yu. A. Kumzerov
中科院分区：
文献类型：
--
作者：
E. Charnaya;C. Tien;W. Wang;Min;D. Michel;D. Yaskov;S. Y. Sun;Yu. A. Kumzerov
给出了两种孔径分别为16 nm和2 nm的多孔玻璃的随机孔网络中液态金属镓的核自旋-晶格驰豫的核磁共振研究结果。测量的温度范围从330K到有限的镓冻结。与块体熔体相比，镓同位素71Ga和69Ga的弛豫都有明显的加速，弛豫的主要机制是从磁性转变为四极。利用四极弛豫贡献数据估算了不同温度下原子运动引起的电场梯度起伏的关联时间，发现与块体相比，电场梯度起伏的关联时间显著增加，这与受限液态镓中原子迁移率的显著减慢相对应。对于较小的孔径，限制的影响更为有效。研究发现，受限镓的关联时间对温度的依赖性明显强于块体，这是在低温下观察到的原子迁移率的额外减慢。
Results of NMR studies of nuclear spin-lattice relaxation in liquid metallic gallium confined within random pore networks of two different porous glasses with 16 and 2 nm pore sizes are presented. The measurements were run in the temperature range from 330 K to confined gallium freezing. Relaxation for both gallium isotopes 71 Ga and 69 Ga was found to accelerate remarkably compared to the bulk melt, the dominant mechanism of relaxation changing from magnetic to quadrupolar. The correlation time of electric field gradient fluctuations caused by atomic motion was estimated at various temperatures using data for quadrupolar relaxation contribution and was found to increase drastically compared to bulk, which corresponded to a pronounced slowdown of atomic mobility in confined liquid gallium. The influence of confinement was more effective for smaller pore sizes. The temperature dependence of the correlation time for confined gallium was found to be noticeably stronger than in bulk, an additional slowdown of atomic mobility being observed at low temperatures.