Theoretical Concept Describing a Use of Magnetic Nanoparticles in a Thin Elastic Film for the Detection of Mechanical Deformation

Herein the effect is analyzed that magnetic dipole interactions have on the heating process of single-domain magnetic nanoparticles subjected to an external radiofrequency (RF) magnetic field, where the magnetic nanoparticles are densely packed in a thin elastic film. To analyze this effect, the considered thin film is subjected to mechanical deformation, which causes the displacement of nanoparticles and affects magnetic dipole interactions between them. As a consequence, at different stages of the mechanical deformation, the film shows different heating powers of the magnetic nanoparticles. To investigate this effect, a theoretical model describing the considered nanoparticle system exposed to the RF magnetic field is proposed, where the heating power of the film is discussed in terms of the specific absorption rates (SARs). Through the use of this model, it is shown that the considered stretchable magnetic film can sense mechanical deformation in the presence of the uniform RF magnetic field both in the direction perpendicular to the film and in the loading direction. Thus, the concept proposed in this study can be utilized in the design of a sensor that would be particularly interesting in the case of medical applications for diagnostic purposes.

Automated summary

The study analyzes the effect of magnetic dipole interactions on the heating process of single-domain magnetic nanoparticles subjected to an external radiofrequency magnetic field. The mechanical deformation of the thin film causes displacement of nanoparticles and affects their interactions, resulting in different heating powers at different stages. The theoretical model proposed in the study demonstrates that the stretchable magnetic film can sense mechanical deformation in the presence of a uniform RF magnetic field, which could be utilized in designing sensors for medical applications.