Structure Peculiarities of Micro- and Nanocrystalline Perovskite Ferrites La1−x Sm x FeO3

Abstract

Micro- and nanocrystalline lanthanum-samarium ferrites La1−xSmxFeO3 with orthorhombic perovskite structure were obtained by using both solid state reactions (x = 0.2, 0.4, 0.6 and 0.8) and sol-gel synthesis (x = 0.5) techniques. Obtained structural parameters of both series of La1−xSmxFeO3 are in excellent agreement with the “pure” LaFeO3 and SmFeO3 compounds, thus proving formation of continuous solid solution in the LaFeO3–SmFeO3 system. Peculiarity of La1−xSmxFeO3 solid solution is divergence behaviour of unit cell dimensions with increasing x: systematic decrease of the a and c lattice parameters is accompanied with increasing b parameter. Such behaviour of the unit cell dimensions in La1−xSmxFeO3 series led to crossover of the a and c perovskite lattice parameters and formation of dimensionally tetragonal structure near x = 0.04. Linear decrease of the unit cell volume of La1−xSmxFeO3 with decreasing x according with the Vegard’s rule indicate absence of short-range ordering of R-cations in the LaFeO3–SmFeO3 system.

Synthesis and Structure Characterisation of Micro-and Nanocrystalline Powders of Dy1-xRxFeO3 (R = La, Pr, Nd, Sm, Gd)

“…3). Such strongly anisotropic behaviour of the unit cell dimensions, which was also recently observed in the related in La 1−x Sm x FeO 3 series [20], is explained by crystal structure peculiarities of the end members of the systems. In spite of being isostructural, DyFeO 3 and LaFeO 3 show different order of the perovskite cell parameters: b p > c p > a p and b p > a p > c p , respectively.…”

Rare-earth-containing perovskite nanomaterials: design, synthesis, properties and applications

“…For example, La1-xSmxFeO3 perovskite was synthesized by SS method, for which La2O3, Sm2O3 and Fe2O3 were milled and annealed in air at 1473 K for 40 h to form micro-scale samples. 167 , And Eu/Pr-doped CaTiO3 can be synthesized by MS method, the raw materials were mixed and ground, then put into muffle furnace annealed at 820 °C for 3.5 h, and the micro-scale spheres were obtained by washing the products with distilled water and ethanol. 131 These two approaches also have common shortcomings: without ligand or organic molecule protection on the surface of the particles, the morphologies and the sizes of desired materials are difficult to control precisely.…”

“Ferrites”: Synthesis, Structure, Properties and Applications

“…The cation A resides at the center, while the arrangement of cation B and the anions X are in the corners and at the edges of the unit cell, respectively [19]. Rare earth ferrites RFeO3 compounds such as orthoferrites of lanthanum and samarium are two most considered materials [20,21]. BiFeO3 [22].…”