Magnetic Compton scattering study of colossal magnetoresistance materials Fe_1-xCu_xCr₂S₄

The spin-polarized electron momentum distributions in the Cr-based chalcogenide spinels Fe_1-xCu_xCr₂S₄ (x = 0.0,0.5,1.0) have been measured using a magnetic Compton scattering technique at T = 10 K. The experimental magnetic Compton profiles have been compared with the results from electronic structure calculations performed using the full potential linearized augmented plane-wave method. The theoretical analysis includes a decomposition of the various orbital and atomic contributions. For x = 0.0 and 0.5 sample compositions, the results show that the magnetic moments of the tetrahedrally coordinated Fe²⁺ (for x = 0.0) and Fe³⁺ (for x = 0.5) with spin moments of 3.66μ_B (for x = 0.0) per formula unit (FU^-1) and 1.6μ_B FU^-1 (for x = 0.5), are aligned antiparallel to those of the octahedrally coordinated Cr³⁺ with spin moments of 5.0μ_B FU^-1 (for x = 0.0) and 4.82μ_B FU^-1 (for x = 0.5). In the ferromagnetic system for x = 1.0, the Cr moment is found to be 5.28μ_B FU^-1.