Text S1.
Figure 1(a) shows the magnetic field surrounding a grade N52 neodymium
bar magnet, which we modeled as a rectangular parallelepiped of size
Lx=4 cm, Ly=4 cm, and
Lz=2 cm, in the x, y, and z directions, respectively.
The magnet is permanently magnetized along the z direction, with a
surface field of 0.5 T. The magnetic field surrounding the magnet is
plotted on the y-z plane. For these calculations, we used the MATLAB
routine FieldBar.m, by Cébron (2021). This routine implements the
analytical equations provided in the section 2.5 of Camacho and Sosa
(2013) but corrects for an error in the equation of the magnetic field
along the y direction and an error in the calculation of the magnetic
field inside the magnet [for details see Cébron (2021)]. The
equations by Camacho and Sosa (2013) are an adaptation for a rectangular
prism magnetized along the z direction of the results obtained by Yang
et al. (1990) for a rectangular prism magnetized along the x direction.
The same routine was also used for the results presented in Figure 1(b).