  Yoke-based permanent magnetic circuits are widely used in Kibble balance
experiments. In these magnetic systems, the coil current, with positive and
negative signs in two steps of the weighing measurement, can cause an
additional magnetic flux in the circuit and hence a magnetic field change at
the coil position. The magnetic field change due to the coil current and
related systematic effects have been studied with the assumption that the yoke
material does not contain any magnetic hysteresis. In this paper, we present an
explanation of the magnetic hysteresis error in Kibble balance measurements. An
evaluation technique based on measuring yoke minor hysteresis loops is proposed
to estimate the effect. The dependence of the magnetic hysteresis effect and
some possible optimizations for suppressing this effect are discussed.
