ON THE NATURE OF THE FIRST-ORDER MAGNETIC PHASE-TRANSITIONS IN MODIFIED MN5SB COMPOUNDS

A considerable change of the electronic specific heat coefficient due the to change of the concentration of the d-electrons by substitution and in an applied magnetic field at the phase transition from antiferr omagnetic (AF) to ferrimagnetic (FI) state was observed in Cr and Co m odified Mn,Sb compounds. At low temperatures, the temperature dependen ce of the AF-FI critical fields shows the T-2 character. The magnetic properties of Mn2Sb-based compounds can be explained by the itinerant magnetism of the d-electrons and by the peculiarities of the electroni c structure.