We studied effect of viscosity on harmonic signals of magnetic nanoparticles (MNP). Harmonic signals are measured when an excitation field with amplitude (~3 mT) and frequency (~10 kHz) is applied, where the relaxation mechanism of the used MNP is affected by the coexistence of Brownian and Néel processes. Viscosity dependence of amplitude and phase of fundamental, third and fifth harmonics are measured when viscosity changed from 0.89 mPa·s to 12.6 mPa·s. The measured viscosity dependences are discussed in terms of field dependent relaxation time of MNP. We also discuss a method to determine temperature and viscosity from the measured harmonic signals.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics