Crystal structure and magnetic properties of Mo-substituted ‘Ba2(Fe,W)2O6’ double-perovskites: a synchrotron diffraction, magnetization and Mössbauer study

Structural and magnetic study of the double‐perovskites Ba 2 (Fe, B′) 2 O 6 (B′ = Mo, W and Re)

“…It results in the magnetic moment observed at saturation lower than the theoretical value [6]. The wide spectrum of the synthetic methods applied by different authors [5,7] hinders interpretation of variety of data concerning structure and magnetic properties of these compounds, because of the possible changing in the cation ordering and the stoichiometry.…”

“…Ba 2 FeMoO 6 and Ba 2 FeReO 6 were found to exhibit a similar magnetic behaviour, involving a ferrimagnetic coupling between iron and molybdenum or rhenium moments, with high Curie temperatures, which depends on the synthetic methods and the inhomogeneities involving Fe/(Mo,Re) site disorder [5,7]. In contrast, there are discrepancies in the description of the magnetic properties of the tungstencontaining compound.…”

“…The double perovskites Ba 2 FeReO 6 , Ba 2 FeMoO 6 and Ba 3 Fe 2 WO 8.42 , synthesized for the first time almost 45 years ago [2,3], were described as cubic with space group Fm 3 m. More recently the Ba 2 (Fe,W) 2 O 6 structure was also reported as tetragonal with space group I4/m based on neutron powder diffraction data [4]. But the carefully performed high-resolution synchrotron diffraction analysis could confirm the initial cubic cell with a = 8.135 Å and with the presence of traces of Fe 3 O 4 [5].…”

Structure and magnetic properties of the double‐perovskites Ba2(B,Re)2O6 (B = Fe, Mn, Co and Ni)

“…The recent finding of the room-temperature tunnelling magnetoresistance effects in the Ba 2 FeReO 6 and Ba 2 FeMoO 6 double-perovskites [1][2][3] revives the study of 3d (B) and 4d/5d (B') transition-metal oxides alloys A 2 BB'O 6 (A = Ba, Ca, Sr). Most of the alloys have been up to now found to take a rock-salt crystal structure, an ordered one of the alternate perovskite units ABO 3 AB'O 3 along three crystallographic axes [4].…”

“…Among the double-perovskite transition-metal oxides, Ba 2 FeReO 6 (Ba 2 FeMoO 6 ) are metallic and ferromagnetic with a critical temperature T C = 318 K (335 K) [3,5]. In these systems, Fe 2+ ions (3d…”