Spontaneous and field-induced magnetic phase transitions in the intermetallic compound DyMn2Ge2

The temperature dependence of lattice constants a and c of intermetallic co mpund DyMn2Ge2 is measured in the temperature range 10 - 800K by using the X-ray method. The magnetoelastic anomaly of lattice constants a is observed at spontaneous magnetic phase transition from paramagnetic state to antife rromagnetic state. The sc magnetic susceptibility of DyMn2Ge2 is measured i n the temperature range 4.2 - 200K. Low temperature magnetic phase transiti ons in DyMn2Ge2 are discussed in the molecular field approximation by takin g into account of next nearest Mn-Mn interlayer exchange interaction. The t emperature dependence of magnetization and magnetic curves at different tem peratures of DyMn2Ge2 single crystal are calculated. Theoretical calculatio n shows that the observed field-induced magnetic phase transition in DyMn2G e2 single crystal at temperature lower than 33K is the transition from ferr imagnetic state into intermediate state.