  In this article, the maximal length of a chain of paramagnetic particles with
magnetic anisotropy in a rotating magnetic field is studied. The theory of
paramagnetic particle chains usually assumes that the particles are
magnetically isotropic and do not rotate in a rotating field. In experiments it
is seen that spherical paramagnetic particles rotate, which can be explained by
small magnetic anisotropy. In this article, the maximal chain length is
calculated for paramagnetic particles with magnetic anisotropy in a rotating
magnetic field. Results show that the maximal chain length as a function of
field frequency has the same trend for isotropic magnetic particles and
particles with magnetic anisotropy if the field frequency is much higher or
much lower than the critical frequency of an individual particle. blue
Initially randomly distributed particles will form chains that will collide and
exchange with particles till they obtain a typical chain length. The typical
chain length of a small cluster is shorter than the maximal chain length of an
isolated chain for the same field frequency. The distribution of chain lengths
in a small cluster of chains is narrower for particles with higher magnetic
anisotropy. Due to the narrower distribution of chain lengths, particles with
magnetic anisotropy can suit better for mass-production. This article will show
how magnetic anisotropy parameters of paramagnetic particles influence chain
length of chains which form in a rotating magnetic field.
