Spin state of cations and magnetoelastic effect in the Mn1−X YbXS

Magnetic moment and magnetization curves of the Mn1−XYbXS (0.05≤Х≤0.2) solid solutions have been experimentally studied at temperatures 4-700 K in magnetic fields up to 9 T. Spin states of manganese and ytterbium ions, the concentration region with the bi- and trivalent states of ytterbium ions are determined. The nonlinear field behavior of the magnetization at X=0.05, the sharp Curie temperature drop and a decrease in the Neel temperature were found. The decrease in the coefficient of thermal expansion with increasing concentration of ytterbium in the magnetically ordered region and the interrelation between the magnetic and elastic subsystems of the Mn1-XYbXS solid solutions have been established.