Synthesis of new double perovskites La1.98Mn1.11Mo0.89O5.93 and La1.92Mn1.29Mo0.71O5.84: Characterization of structural and magnetic properties

JOURNAL OF ALLOYS AND COMPOUNDS

卷:681

Article

Fuster, V.¹  Blanco, M. C.²  Franco, D. G.^3,4  Tirao, G.⁵  Nassif, V. M.⁶  Nieva, G.³  Carbonio, R. E.² 

[1] CONICET UNR, Inst Fis Rosario, Bv 27 Febrero 210 Bis, RA-2000 Rosario, Argentina

[2] Univ Nacl Cordoba, Fac Ciencias Quim, Dept Fisicoquim, INFIQC,CONICET UNC, Medina Allende,Ciudad Univ,X5000HUA, Cordoba, Argentina

[3] CNEA, Ctr Aom Bariloche, Av Ezequiel Bustillo 9500,8400 SC, San Carlos De Bariloche, Rio Negro, Argentina

[4] Inst Balseiro UNCuyo, Av Ezequiel Bustillo 9500,8400 SC, San Carlos De Bariloche, Rio Negro, Argentina

[5] Univ Nacl Cordoba, Fac Matemat Astron & Fis, IFEG, CONICET, Medina Allende,X5000HUA, Cordoba, Argentina

[6] CNRS, Inst NEEL, 25 Ave Martyrs, F-38042 Grenoble, France

关键词: Magnetically ordered materials;    Crystal structure;    Vacancy formation;    Magnetic measurements;    Neutron diffraction;    Order-disorder effects;   

DOI  :  10.1016/j.jallcom.2016.04.169

来源: Elsevier

【 摘 要 】

The synthesis, structural and magnetic characterization of two new perovskites La1.98Mn1.11Mo0.89O5.93 and La1.92Mn1.29Mo0.71O5.84 are reported. Combined Rietveld refinements of X-ray and neutron powder diffraction data indicate that both samples are monoclinic perovskites with space group P2(1)/n. The distribution of the transition metals over the octahedral sites is highly ordered: Mn preferentially occupies 2c sites, while Mo mostly occupies 2d sites. Mn oxidation states were determined by means of high resolution KO Emission Spectroscopy. The susceptibility as a function of temperature measurements and hysteresis loops show complex magnetic behaviour of both perovskites. The refined magnetic cells indicate that La1.98M1.11Mo0.89Mo0.89O5.93 is ferrimagnetic as a result of the antiferromagnetic coupling of two ferromagnetic sub-lattices associated to 2d and 2c sites, while La1.92Mn1.29Mo0.71O5.84 is ferromagnetic due to ferromagnetic alignment of the two sub-lattices. The magnetic overall behaviour of the latter peroyskite is interpreted in terms of delocalization of magnetic moments arising from ferromagnetic double-exchange interactions between Mn2+ and Mn3+. (C) 2016 Elsevier B.V. All rights reserved.

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