Longitudinal spin dynamics in nickel fluorosilicate

The existense of single-ion anisotropy leads to the effect of the quantum spin reduction. This gives rise to a purely longitudinal magnetization dynamics, which coupled oscillations of the spin modulus and quadrupole quantum mean values built on the spin operators. For nickel fluorosilicate consists in of the effect of quantum spin reduction may be controlled by changing the pressure. The study of the longitudinal nonlinear spin dynamics and the analysis of possible photomagnetic effects show that this compound is a convenient model object to realize the switching of the magnetization direction under the action of femtosecond laser pulses