Affiliation:
1. Mikheev Institute of Metal Physics, Ural Branch, Russian Academy of Sciences
2. Pyzhyanov Institute of Metallurgy, Ural Branch, Russian Academy of Sciences
Abstract
We study the structural, magnetic, and optical properties of double manganites LnBaMn2O6 with Ln = Pr, Nd, Sm, Nd1 – xSmx (x = 0.25, 0.5, 0.75). Analysis of the temperature dependences of transmission in the near IR range has shown the difference in the responses of the charge subsystem for different types of charge/orbital ordering in the system. In PrBaMn2O6 manganite, the orbital ordering of the dx2−y2 type leads to an insulator state at low temperatures. The charge subsystem of manganites NdBaMn2O6, Nd0.75Sm0.25BaMn2O6, and Nd0.5Sm0.5BaMn2O6 is sensitive to the orbital ordering type: in the temperature interval TCO2 T TCO1, where pairwise alignment of layers with d3x2−r2/d3y2−r2 ordered orbitals is realized, the semiconductor character of charge carriers is observed, while upon a transition to the layer-by-layer alignment of orbitally ordered layers for T TCO2, charge carriers are of the metal character. In manganites Nd0.25Sm0.75BaMn2O6 and SmBaMn2O6, the absence of clearly manifested metal nature of the charge subsystem at T TCO2 is associated with the formation of the antiferromagnetic ordering of the CE type.
Publisher
The Russian Academy of Sciences
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