Synthesis, structural characterization and magnetic properties of the series of double perovskites Ba1+xLa1-xMnSbO6 with 0.1 ≤ x ≤ 0.7

JOURNAL OF ALLOYS AND COMPOUNDS

卷:704

Article

Arciniegas Jaimes, Diana M.¹  Cecilia Blanco, M.¹  Pomiro, Fernando¹  Tirao, German²  Nassif, Vivian M.^3,4  Cuello, Gabriel J.⁵  Alonso, Jose A.⁶  Carbonio, Raul E.¹ 

[1] Univ Nacl Cordoba, Fac Ciencias Quim, CONICET, INFIQC,Dept Fisicoquim, Haya Torre Esq,Medina Allende,Ciudad Univ,X5000HU, Cordoba, Argentina

[2] Univ Nacl Cordoba, Fac Matemat Astronomia & Fis, CONICET, IFEG, Haya Torre Esq,Medina Allende,X5000HUA, Cordoba, Argentina

[3] Univ Grenoble Alpes, F-38000 Grenoble, France

[4] CNRS, Inst NEEL, F-38042 Grenoble, France

[5] Inst Laue Langevin, 71 Av Martyrs,CS20156, F-38042 Grenoble 9, France

[6] Inst Ciencia Mat Madrid, Sor Juana Ines Cruz 3, Madrid 28049, Spain

关键词: Double perovskites;    Crystal structure;    Magnetic measurements;    Powder neutron diffraction;    Order-disorder effects;    X-ray emission spectroscopy;   

DOI  :  10.1016/j.jallcom.2016.12.308

来源: Elsevier

【 摘 要 】

Double perovskites Ba1+xLa1-xMnSbO6 were synthesized by traditional ceramic methods in air as polycrystalline powders. The 0.1 <= x <= 0.2 compounds belong to the 12/m monoclinic space group, while the perovskites with x >= 0.3 belong to the I 4/m tetragonal space group. The effective presence of mixtures of Mn2+/Mn3+ has been well established by X-ray Emission Spectroscopy. Ba1+xLa1-xMnSbO6 (0.1 <= x <= 0.5) oxides display signs of superparamagnetism in the 40-160 K range, which arises from 3D-nanoclusters formed in regions which are rich in Mn2+/3(+)-O-Mn2+/(3+) superexchange paths originated by the antisite disorder. The analysis of the M vs H hysteresis loops shows that, as x increases, the number of 3D-nanoclusters rises and the number of magnetic ions in the 3D-nanoclusters decreases. The small 3D-nanoclusters cannot sustain magnetic order inside them and this is the reason for the absence of superparamagnetism for x = 0.6 and 0.7. The analysis of the M vs H curves also shows the presence of a weak ferromagnetism which is generated by the canting of the spins in the antiferromagnetic matrix. Neutron Powder Diffraction data reveals that there is long range antiferromagnetic ordering below =20 K. (C) 2016 Elsevier B.V. All rights reserved.

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