Fig. 2: Single-particle dynamics.
From: Thermally active nanoparticle clusters enslaved by engineered domain wall traps
a Two trajectories of one paramagnetic nanoparticle trapped above a magnetic bubble for Bz = 0 mT (black line) and Bz = 4.7 mT (red line), the circles indicate the corresponding locations of the Bloch wall. b Magnetic potential U1(r) calculated from the particle fluctuations for different values of the applied field Bz. Scattered points are experimental data, continuous lines are fit using a simple harmonic approximation, U1(r) = ker2/2. c Spring constant ke of the potential measured for different magnetic field Bz. Continuous red line denotes linear fit with ke = k0 + k1Bz, with k0 = 0.0129 ± 0.0012 pN/μm and k1 = 0.0043 ± 0.0005 pN/(mTμm). The error bars in the data result from the statistical average of different measurments. d Log–log plot of the mean-square displacement (MSD) for different applied magnetic fields. Continuous lines are fits obtained by using the theoretical model, see Eq. (2) and text.
