When an alternating electromagnetic field off, leaving only the z-axis direction of the applied static magnetic field B0, so that the magnetization vector M0 precess along B0.
When the intersection electromagnetic field is closed, only the applied static magnetic field B0 in the direction of the z-axis is retained, so the magnetized vector M0 will move along B0.
When the alternating electromagnetic field is turned off, only the external static magnetic field B0 in the z-axis direction is retained, so the magnetization vector M0 will advance along B0.<br>