SAW Investigation of Structural Changes in Oil-Based Magnetic Fluids |
| P. Burya, F. Černobilaa, M. Veveričíka, J. Kúdelčíka, P. Kopčanskýb, M. Timkob, M. Rajňákb
aDepartment of Physics, Žilina University, Univerzitná 1, 010 26 Žilina, Slovakia bInstitute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia |
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| Structural changes in transformer oil-based magnetic fluids under magnetic fields are investigated using surface acoustic waves. The measurement of the attenuation of SAW propagating along the interface between magnetic fluid and substrate is showed as an effective tool to study such processes in the cases when the obviously utilized longitudinal acoustic waves due to the higher viscosity are not available. The magnetic particles FeO·Fe2O3 in several different volume concentrations were added to the transformer oil MOL. The interactions between magnetic field and magnetic moments of nanoparticles lead to the aggregation of magnetic nanoparticles and subsequent chain or cluster formations that have the influence on the SAW attenuation. Temperature of magnetic fluids has also very important influence on structural changes due to the change of viscosity and thermal motion with increasing temperature that both affect the process of cluster creation. The measurement of the acoustic anisotropy gives additional useful information about the structure of nanoparticles formations. |
DOI:10.12693/APhysPolA.137.964 topics: magnetic fluids, structural changes, SAW |