| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 1798984 | Journal of Magnetism and Magnetic Materials | 2015 | 5 Pages |
•Magnetic structure of the compounds has been clarified by NPD.•Magnetic properties of the compounds has been explained using superexchange scenario.•Mn–O–Fe and Fe–O–Fe superexchange interactions are strongly antiferromagnetic.
Magnetic properties and crystal structure of La0.7Sr0.3Mn1−xMexO3 (Me=Ga, Fe, Cr; x≤0.3) have been studied by neutron powder diffraction and magnetization measurements. It is shown that substitution of manganese ions by chromium or gallium ions (x=0.3) leads to phase separation into antiferromagnetic and ferromagnetic phases whereas replacement by Fe ions stabilizes spin glass state (x=0.3). Ferromagnetic interactions in Cr-substituted compounds are much more pronounced than in Fe- and Ga-doped ones. Magnetic properties are discussed in the model assuming a dominance of superexchange interactions. It is considered that ferromagnetism in the Cr-substituted compositions is associated with nearly equal contributions from positive and negative components of the superexchange interaction between Mn3+ and Cr3+ ions as well as to mixed valence of chromium ions. The spin glass state observed for the Fe-doped sample (x=0.3) is associated with strong antiferromagnetic superexchange between Fe3+–O–Fe3+ and Fe3+–O–(Mn3+, Mn4+).
