Relaxation attenuation of ultrasound by the jahn-teller centers in ZnSe:Cr in high magnetic fields

The magnetic field dependence of ultrasonic attenuation α(B) of slow shear waves in the ZnSe:Cr²⁺ crystal at a number of fixed temperatures from T = 1.4 K to 20 K in magnetic fields of up to B = 14 T was investigated. For magnetic fields B above 5 T we found that the attenuation increases with B monotonically, and at a given temperature it is proportional to the magnitude of relaxation attenuation at B = 0. We show that the magnetic field dependent attenuation is due to the change in populations of the lowest energy levels of the impurity centers Cr_Zn4Se, produced by the Jahn-Teller effect and split by the spin-orbital interaction and the magnetic field. The calculations carried out without fitting parameters are in good agreement with the experimental data.