Original Paper Ann. Phys. (Berlin) 527, No. 3–4, 248–253 (2015) / DOI 10.1002/andp.201400174 Difusion slowdown in the nanostructured liquid Ga-Sn alloy Dmitri Y. Podorozhkin 1 , Elena V. Charnaya 1,∗ , Min Kai Lee 2,3 , Lieh-Jeng Chang 2 , Juergen Haase 4 , Dieter Michel 4 , Yurii A. Kumzerov 5 , and Alexsandr V. Fokin 5 Received 20 August 2014, revised 18 November 2014, accepted 9 December 2014 Published online 13 January 2015 The difusion of gallium in liquid Ga-Sn alloy embedded into diferent porous silica matrices was studied by NMR. Spin relaxation was measured for two gallium isotopes, 71 Ga and 69 Ga, at two magnetic felds. Pronounced rise of quadrupole contribution to relaxation was observed for the nanostructured alloy which increased with decreasing the pore size. The correlation time of atomic mobility was eval- uated and found to be much larger than in the relevant bulk melt which evidenced a pronounced difusion slowdown in the Ga-Sn alloy under nanoconfnement. It is shown that the difusion was slower by a factor of 30 for the alloy within 7 nm pores. The spectral densities of electric feld gradients at zero frequency were found to double for the fnest pores. The Knight shif was found to decrease but slightly for the nanostructured alloy. 1 Introduction Studies of diffusion processes in liquid metals and al- loys are of great importance for understanding the mass transport and dynamics in melts, solidification, vitrifica- tion, and crystal growth. Information about atomic mo- bility in metallic liquids is also vital for many techno- logical applications. However, accurate measurements of diffusion coefficients meet many problems [1, 2]. The most reliable data on self-diffusion in bulk melts are pro- vided by the quasielastic neutron scattering technique, in particular, on levitated metallic droplets [1, 3]. The problem of self-diffusion studies in liquid metallic thin films and other low-dimensional systems becomes even more complicated due to strong slowdown of atomic mobility in nanostructured melts beyond the sensitivity limits of neutron scattering [4]. Recently it was shown that information about self-diffusion in nanostructured metallic liquids can be obtained by NMR through mea- surements of nuclear spin relaxation [5]. The slowdown of self-diffusion leads to drastic acceleration of spin relaxation for quadrupole nuclei which is related to the correlation time of atomic mobility and further to the dif- fusion coefficient. In this case the correlation time can be directly calculated from the quadrupole contribution to nuclear spin relaxation while in solids more complicated experiments might be necessary [6]. This method was successfully applied to get data on mobility in small par- ticles and thin films of melted indium, gallium, and their alloy [7–9]. To extend the knowledge of the influence of size reduction on self-diffusion in metallic melts we car- ried out studies of atomic mobility in the nanostructured liquid gallium-tin alloy. The results of these studies are the subject of the present paper. 2 Samples and experiments To study the atomic mobility in the nanostructured liquid gallium-tin alloy, it was embedded into pores of three kinds of silica porous matrices: porous glasses with mean pore diameters 7 and 18 nm and opal matrix. The porous glasses were made by acid leaching the phase- separated alkali-borosilicate glasses. After leaching the pores formed a thoroughly interconnected network. Pore sizes were determined by nitrogen adsorption- desorption isotherms and mercury porosimetry. According to the mercury porosimetry about 80% of total void volume corresponds to pores lying within the ∗ Corresponding author: charnaya@live.com, Tel. +7 812 4284330, Fax +7 812 4287240 1 Institute of Physics, St. Petersburg State University, St. Petersburg, 198504 Russia 2 Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan 3 NSC Instrument Center at NCKU, Tainan, 70101 Taiwan 4 Faculty of Physics and Geophysics, Leipzig University, Leipzig, D- 04103 Germany 5 A. F. Iofe Physico-Technical Institute RAS, St. Petersburg, 194021 Russia 248 C  2015 by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim