Quantum dynamics of molecular magnets in ultra-fast sweeping magnetic fields

Non-equilibrium magnetization process of a S=((1)/(2)) spin triangle in molecular magnet V15 has been studied by using fast sweeping pulsed magnetic fields. In the up sweep, the magnetization jump of about 1μB is found at the level crossing between the ground S=((1)/(2)) and the excited S=((3)/(2)) states, while it is about 2μB in the down sweep. The jump in the up sweep is half of that expected in the equilibrium magnetization process. This phenomenon is interpreted by considering the difference of mixing in two degenerated S=((1)/(2)) states with the S=((3)/(2)) state