  Broadening the knowledge and understanding on the magnetic correlations in
van der Waals layered magnets is critical in realizing their potential
next-generation applications. In this study, we employ high frequency (240 GHz)
electron spin resonance (ESR) spectroscopy on plate-like CrBr$_{3}$ to gain
insight into the magnetic interactions as a function of temperature (200 - 4 K)
and the angle of rotation ${\theta}$. We find that the temperature dependence
of the ESR linewidth is well described by the Ginzberg-Landau critical model as
well as Berezinskii-Kosterlitz-Thouless (BKT) transition model, indicative of
the presence of two-dimensional (2D) correlations. This suggests that the
three-dimensional ferromagnet CrBr$_{3}$, which has been described as an Ising
or Heisenberg ferromagnet, could present 2D magnetic correlations and BKT-like
behavior even in its bulk form; an observation that, to the best of our
knowledge, has not been reported in the literature. Furthermore, our findings
show that the resonance field follows a $(3cos^2{\theta} - 1)$-like angular
dependence, while the linewidth follows a $(3cos^2{\theta} - 1)^2$-like angular
dependence. This observed angular dependence of the resonance field and
linewidth further confirm an unanticipated 2D magnetic behavior in CrBr$_{3}$.
This behavior is likely due to the interaction of the external magnetic field
applied during the ESR experiment that allows for the mediation of long-range
vortex-like correlations between the spin clusters that may have formed due to
magnetic phase separation. This study demonstrates the significance of
employing spin sensitive techniques such as ESR to better understand the
magnetic correlations in similar van der Waals magnets.
