Magnetic phase diagram of the intermetallic compounds Gd1-xLaxMn2Ge2 and the effect of a field on transitions of the Mn subsystem from the antiferromagnetic into the ferromagnetic state

The magnetic properties of the intermetallic compounds Gd1 - xLaxMn2Ge2 (la yered tetragonal crystal structure of the type ThCr2Si2), investigated in t he present work and in [1] A. Sokolov, et al., Sol. State Commun. 105, 289 (1998), are discussed. It is shown that the basic characteristics of the ma gnetic ordering of these compounds-magnetic phase transitions from the ferr imagnetic into the antiferromagnetic state and vice versa-observed with inc reasing temperature in compositions with x < 0.1, the effect of a magnetic field on these transitions, the temperature dependences of the magnetizatio n of these intermetallic compounds, as well as their magnetic T-x diagram c an be described quantitatively in the Yafet-Kittel model for ferrimagnets w ith a negative exchange interaction in one of the sublattices using paramet ers determined in [2] A. Yu. Sokolov et al., JETP 89, 723 (1999) from inves tigations of the system Gd1 - xYxMn2Ge2, taking into account the dependence of the interplanar exchange interaction Mn-Mn on the crystal lattice param eter a. (C) 2000 MAIK "Nauka / Interperiodica".