MOLECULAR-DYNAMICS METHOD TO ITINERANT MAGNETS WITH COMPLEX MAGNETIC-STRUCTURE

A molecular dynamics method which allows us to determine the magnetic structures of itinerant magnets with a few hundred atoms in a unit cel l has been developed on the basis of the functional integral method. T he method yields the generalized Hartree-Fock approximation at the gro und state, and describes the finite temperature magnetism accompanied by the second order phase transition. The results for fee transition m etals with the use of 108 atoms in a unit cell show a complex antiferr omagnetic (AF) structure for the d electron number n(d)=6.0, the first -kind AF for n(d)=6.2, the helical structure with Q=(0,1/3,1)2 pi/a fo r n(d)=6.4, the helical structure with the same Q but with modulated a mplitudes of local moments for n(d)=6.6. A helical structure with Q=(0 ,1/3,2/3)2 pi/a is obtained for gamma-Fe. (C) 1997 American Institute of Physics.