  Quantum dynamics of anisotropic spin system with large spin moment in a swept
magnetic field is theoretically investigated. Magnetic field of this type
induces vortex static electrical field, that breaks down the axial symmetry and
induces new coherent quantum phenomena: the occurrence of band energy spectrum
with continuous spin states, Bloch-type oscillations and interband Zener
tunnelling effect. These quantum phenomena display themselves, in particular,
in magnetization jumps and susceptibility peaks in the investigated spin
system.
