Structural and magnetic properties of La0.7Sr0.3Mn1-xCrxO3 (0 < x ≤ 0.7) have been studied in order to determine the effect of substitution of Cr3+ for Mn3+. The data consist of neutron and x-ray powder-diffraction and magnetization measurements. We previously suggested these systems transition from ferromagnetic to antiferromagnetic ordering with the intermediate concentrations containing coexisting ferromagnetic and antiferromagnetic domains. Upon further detailed examination, we find that the neutron data can be fit using a single homogeneous long-range magnetically ordered state and compositionally dependent charge ordering. The magnetic structures are controlled by the competition between Mn-Mn, Mn-Cr, and Cr-Cr interactions (double exchange and superexchange). The metal to semimetal and semimetal to insulator transitions can be quantitatively described as due to the localization effect of superexchange. The presence of charge ordered states in the insulating region arises from the favorable energetics of Mn4+-O-Cr3+ superexchange bonds relative to Mn3+-O-Cr3+ bonds.
T. F. Creel et al., "Neutron and Magnetic Studies of La₀.₇Sr₀.₃Mn₁₋ₓCrₓO₃(x ≤ 0.7): A Homogeneous Charge-Ordered System," Physical review B: Condensed matter and materials physics, vol. 93, no. 8, American Physical Society, Feb 2016.
The definitive version is available at https://doi.org/10.1103/PhysRevB.93.085116
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01 Feb 2016