Kinetics of magnetostriction of ferrogel with physical networking based on natural polysaccharide guar gum with embedded strontium hexaferrite magnetic particles were studied in the uniform magnetic field 420 mT. An ellipsoidal sample was elongated by 37% along the applied field and contracted by 15% in the transverse direction, while its volume was kept constant. The characteristic time of magnetostriction was 440 s. Dynamic mechanical analysis in an oscillatory mode showed that the deformation of ferrogel is mostly elastic rather than viscous. Its storage modulus was almost constant in a frequency range of 0.1–100 Hz and by at least an order of magnitude larger than the loss modulus. Meanwhile, a developed theoretical model based on the elasto-viscous behaviour of the ferrogel failed to estimate correctly the experimental value of its magnetostriction. Calculated values of the elongation of ferrogel in the field were several orders of magnitude lower than those observed in the experiment for the ferrogel with physical networking. Consistency between the experiment and the theory was achieved using the alternative consideration based on the deformation of a liquid droplet of ferrofluid. The applicability of such an approach was discussed concerning structural relaxation properties of the ferrogel with physical networking.

This article is part of the theme issue ‘Transport phenomena in complex systems (part 1)’.

在420 mT的均匀磁场中研究了基于天然多糖瓜尔胶和嵌入六铁氧体锶磁性颗粒的物理网络铁凝胶的磁致伸缩动力学。椭圆体样品沿外加场伸长 37%，横向收缩 15%，而其体积保持不变。磁致伸缩的特征时间为440 s。振荡模式下的动态力学分析表明，铁凝胶的变形主要是弹性的而不是粘性的。它的储能模量在 0.1-100 Hz 的频率范围内几乎是恒定的，并且至少比损耗模量大一个数量级。同时，基于铁凝胶的弹性粘性行为的发展理论模型未能正确估计其磁致伸缩的实验值。铁凝胶在现场的伸长率计算值比物理网络铁凝胶实验中观察到的值低几个数量级。使用基于铁磁流体液滴变形的替代考虑实现了实验和理论之间的一致性。讨论了这种方法的适用性，涉及具有物理网络的铁凝胶的结构弛豫特性。使用基于铁磁流体液滴变形的替代考虑实现了实验和理论之间的一致性。讨论了这种方法的适用性，涉及具有物理网络的铁凝胶的结构弛豫特性。使用基于铁磁流体液滴变形的替代考虑实现了实验和理论之间的一致性。讨论了这种方法的适用性，涉及具有物理网络的铁凝胶的结构弛豫特性。

本文是主题问题“复杂系统中的传输现象（第 1 部分）”的一部分。