Magnetic phase transitions in Ln 1–x Sr x Co0.5Mn0.5O3 (Ln = La, Pr, Nd, and Eu)
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The system of La1–x Sr x Co0.5Mn0.5O3 solid solutions have been studied by neutron diffraction and the measurement of the magnetization. The composition with x = 0 has the monoclinic structure (space group P21/n); the compositions with 0.15 ≤ x ≤ 0.6 are rhombohedral (R \(\bar 3\) c), and the composition with x = 0.75 is cubic (Pm \(\bar 3\) m). All the compositions with x ≤ 0.75 are shown to contain a ferromagnetic component. The stoichiometric composition with x = 0.5 undergoes a sharp ferrromagnet–paramagnet transition at 240 K; however, no coherent magnetic contribution to the neutron diffraction has been detected. The magnetic data are interpreted, assuming that the ferromagnetism at x ≤ 0.15 is due to positive superexchange Co2+–O–Mn4+ interaction, while, at x ≥ 0.25, the superexchange interaction between ions Co3+ in a high-spin state and ions Mn4+ is responsible for the ferromagnetic component.
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- 9.A. J. Barón-González, C. Frontera, J. L. García-Muõz, J. Blasco, and C. Ritter, J. Phys.: Conf. Ser. 325, 012007 (2011).Google Scholar