Spin-polarized electron momentum density distributions [formula omitted

Abstract

The spin-polarized electron momentum distributions (EMD) for ferrimagnetic GdMn 2Ge 2 and ferromagnetic LaMn 2Ge 2 have been measured using the magnetic Compton scattering technique. The spin-polarized EMDs were resolved along the c-axis at 15 K . In the Gd sample, the Gd and Mn spin sublattices are aligned antiparallel with spin moments of 6.8±0.1 μ B per formula unit (FU −1) and 3.7±0.1μ B FU −1 , respectively, with the Gd spin sublattice oriented parallel to the scattering vector. The ferromagnetic La system exhibits no 4f moment and the Mn moment is aligned parallel to the scattering vector, the ordered spin moment on the Mn being 2.4±0.1μ B FU −1 . The two samples measured are the extreme points of the phase diagram for Gd 1− x La x Mn 2Ge 2. Our data give a direct indication of the sublattice reorientation at x≈0.5, implied from previous magnetization measurements and indicate that at a low temperature the Mn sublattice is a canted ferromagnetic system.