X-ray powder diffraction refinement of PbTi_(1−x)Fe_xO_(3−δ) solid solution series

Abstract

A series of iron-doped lead titanate PbTi(1−x)FexO(3−δ) samples in the x = 0–1 composition range was prepared using sol–gel synthesis at a calcination temperature of 700 °C. The room temperature CuKα powder diffraction data collected from x = 0, 0.005, 0.01, 0.025, 0.05, 0.075, 0.1, 0.125, 0.15, 0.175, 0.2, and 0.3 samples were analyzed using the Rietveld method. Magnetoplumbite (PbFe12O19) secondary phase formation was observed at compositions x = 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, and 1. Fe-composition dependent decrease of tetragonal distortion has been observed. According to Vegard's law, the B-site iron solubility limit in the lead titanate host was found to be approximately 10 mol% (x = 0.1). Homogeneous distribution of dopants below the solubility limit was evidenced by the linear behavior of unit-cell parameters. The absence of a cubic phase and the persistence of distorted oxygen octahedra indicated the existence of ferroelectric properties even at the x = 0.3 composition. Beyond x = 0.3, the P4mm tetragonal model was determined to be invalid possibly because of oxygen defect driven structural changes, mainly tilting Fe-polyhedra.

Structural, optical and vibrational properties of self-assembled Pbn+1(Ti1−xFex)nO3n+1−δ Ruddlesden-Popper superstructures

“…For PTFO powder samples a single perovskite phase is retained only for Fe fractions x ≤ 0.3, while x > 0.3 exhibits secondary phases visible as additional XRD peaks, and consisting mainly of PbFe 12 O 19 18. Here, the extra peaks visible in the XRD ω − 2 θ scans arise from the RP superstructure, and no evidence of such secondary phases was observed via XRD or TEM.…”

“…Recently, PbTi 1− x Fe x O 3− δ has been reported to be multiferroic at room temperature16. PbTiO 3 is a displacive ferroelectric17 that exhibits a tetragonal bulk phase with space group P4mm1819. Ferroelectric polarisation arises from the displacement of Ti 4+ ions with respect to the surrounding oxygens.…”

“…Ferroelectric polarisation arises from the displacement of Ti 4+ ions with respect to the surrounding oxygens. The partial substitution of Fe on the B site allows magnetism to be induced, but causes a reduction in the tetragonal distortion c / a and a concommitant decrease in the remnant polarization18202122. Similar to other multiferroics the use of thin films23 and nanoparticles202124 may enhance ferroelectricity and ferromagnetism in comparison to the bulk phase.…”

Trapping of Oxygen Vacancies at Crystallographic Shear Planes in Acceptor‐Doped Pb‐Based Ferroelectrics

“…TheX PD patterns of the PbTi 1-z Fe z O 3-d solid solutions prepared using wet chemistry at 700 8 8Cd on ot demonstrate the reflection splitting expected for the CS structure at least up to z = 0.5, but raising the annealing temperature to 850 8 8C and 1000 8 8Cp roduces XPD patterns characteristic of CS planes. [21] At high doping levels,F e III -doped PbTiO 3 develops antiferromagnetic order,w hich is seen in the room-temperature NPD pattern of the z = 0.95 sample ( Figure S9). Te mperature dependence of the magnetic susceptibility for the z = 0.9 sample indicates an antiferromagnetic transition with the NØel temperature of T N = 485 K ( Figure 4, bottom).…”

“…%P bO was added on the second-last annealing.T he softchemistry procedure was similar to that reported in Ref. [21],and the details are given in the Supporting Information.…”