Preparation, structural, dielectric and magnetic properties of LaFeO3–PbTiO3 solid solutions

Solid solutions of (1−x)LaFeO3–(x)PbTiO3 (0 < x < 1) have been prepared by conventional solid-state reaction. These complex perovskites have been studied by means of X-ray (XRPD) and neutron powder (NPD) diffraction, complemented with dielectric, magnetic, heat capacity and Mössbauer measurements. Complete solubility in the perovskite series was demonstrated. The NPD and XRPD patterns were successfully refined as orthorhombic (x ≤ 0.7) and tetragonal (x ≥ 0.8). A composition-driven phase transformation occurs within the interval 0.7 < x < 0.8. The samples with x < 0.5 showed evidence of long-range magnetic ordering with an G-type antiferromagnetic arrangement of the magnetic moments of the Fe3+ cations in the B-site with propagation vector k = (0,0,0). Based on the obtained experimental data, a combined structural and magnetic phase diagram has been constructed. The factors governing the structural, dielectric and magnetic properties of (1−x)LaFeO3–(x)PbTiO3 solid solutions are discussed, as well as their possible multiferroicity.

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► Solid-solutions of (1−x)LaFeO3–(x)PbTiO3 were synthesized by solid-state reaction.
► XRPD and NPD evidence orthorhombic (x < 0.7) and tetragonal (x > 0.8) crystal structures.
► LaFeO3-rich compositions order antiferromagnetically (x < 0.6, G-type structure).
► PbTiO3-rich compositions exhibit ferroelectric order (x larger than 0.8).
► Magnetic and dielectric (relaxor) ordering coexist near room-temperature around x = 0.4.