  Spin and orbital angular momentum of light plays a central role in quantum
nanophotonics as well as topological electrodynamics. Here, we show that the
thermal radiation from finite-sized bodies comprising of nonreciprocal
magneto-optical materials can exert a spin torque even in global thermal
equilibrium. Moving beyond the paradigm of near-field heat transfer, we
calculate near-field radiative angular momentum transfer between finite-sized
nonreciprocal objects by combining Rytov's fluctuational electrodynamics with
the theory of optical angular momentum. We prove that a single magneto-optical
cubic particle in non-equilibrium with its surroundings experiences a torque in
the presence of an applied magnetic field (T-symmetry breaking). Furthermore,
even in global thermal equilibrium, two particles with misaligned gyrotropic
axes experience equal magnitude torques with opposite signs which tend to align
their gyrotropic axes parallel to each other. Our results are universally
applicable to semiconductors like InSb (magneto-plasmas) as well as Weyl
semi-metals which exhibit the anomalous Hall effect (gyrotropy) at infrared
frequencies. Our work paves the way towards near-field angular momentum
transfer mediated by thermal fluctuations for nanoscale devices.
