Structural and magnetic characterization of the double perovskite Pb₂FeMoO₆

High-Pressure Synthesis and Ferrimagnetic Ordering of the B-Site-Ordered Cubic Perovskite Pb2FeOsO6

“…Here a p indicates the lattice constant for a simple cubic ABO 3 perovskite. The absence of a diffraction peak with h + k , k + l , and h + l = odd suggests face-centering of the unit cell . The Rietveld analysis demonstrates that PFOO crystallizes into a B-site-ordered perovskite structure with space group Fm 3̅ m .…”

“…The absence of a diffraction peak with h + k, k + l, and h + l = odd suggests face-centering of the unit cell. 23 The Rietveld analysis demonstrates that PFOO crystallizes into a B-site-ordered perovskite structure with space group Fm3̅ m. In this symmetry, all of the cations occupy fixed atomic positions at 8c (0.25, 0.25, 0.25) for Pb, 4a (0, 0, 0) for Fe, and 4b (0.5, 0.5, 0.5) for Os, and the O is also located at a special site 24e (x, 0, 0). 24 This means that the only variable position parameter is O x , which determines the Fe−O and Os−O distances.…”

Colossal magnetoresistance in the insulating ferromagnetic double perovskites Tl2NiMnO6: A neutron diffraction study

“…This, in turn, points to a tendency of the AS defects to form clusters (regions with high concentration of AS defects). Such a tendency is also observed in A2FeMoO6 (A=Sr 2+ , Pb 2+ ) compounds in which the clustering of AS defects was proved using local probes [15,45]. As it will be shown below this in fact has a significant influence on the magnetic properties of the system.…”

“…In ordered double perovskites, with chemical formula A2BB'O6 (A= rare earth or alkaline, B/B'= transition metal), B and B' cations generally form either rock-salt or layered type superstructure. The former, which leads to alternate stacking of BO6/B'O6 octahedra, is the most common type to minimize the electrostatic energy arising from the different charges of the two cations, and/or the elastic energy due to their different ionic sizes [8][9][10][11][12][13][14][15][16]. When the radius or the charge of B and B' cations is similar, the probability of antisite (AS) defects (partial occupation of B cations in B' sites and vice versa) increases up to a fully disordered state, effectively tuning the macroscopic properties of the system [11].…”

Oxygen deficient perovskites: effect of structure on electrical conductivity, magnetism and electrocatalytic activity.

“…In addition, the maximum magnetization at 9 T is ~1.28 μB, much lower than that anticipated The absence of hysteresis in the isothermal magnetization at 2 K indicates that the ferrimagnetic interactions are not long-range, and occur in short-range scale, similar to the situation in superparamagnetic systems. 177 The significantly different magnetic properties between the two isostructural materials is interesting. The magnetic susceptibility of BaSrCo2O6-δ deviates from paramagnetism in the entire temperature range, 2-400 K. The very low magnetization values even at 2 K and 9 T, indicate antiferromagnetic order in BaSrCo2O6-δ, consistent with a report on a similar material.…”