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The hydrothermal synthesis and magnetic, dielectric and ferroelectric property characterization of ABO-perovskite GdFeCrO (0 < x < 1) are reported. The mineralizer KOH plays a critical role in the perovskite structure of the sample. The Fe/Cr ratio of the final crystal is controlled by the alkalinity in the initial reaction mixtures. The lattice parameters and magnetic ordering transition temperature have a close relationship with the Fe/Cr ratio. The temperature dependent magnetic properties of GdFeCrO (0 < x < 1) samples show a close relationship with substituent ratios of Cr. The occurrence of ferromagnetic behavior in all of the as-prepared samples comes from the coexistence of canted-antiferromagnetism due to the double exchange effect of Fe-O-Fe and Cr-O-Cr and ferromagnetism due to superexchange interaction of Fe-O-Cr. A large spontaneous polarization was observed in GdFeCrO at room temperature, exhibiting a clear ferroelectric hysteresis loop, which indicates the ferroelectric behavior in this system. This work not only provides an effective route to the controllable synthesis of B-site doped REFeCrO perovskite structure materials, but also presents a comprehensive study of the tunable effect of ionic doping on ferroelectric properties.

Five highly stable coordination polymers assembled by 2-(2-carboxyphenyl)imidazo(4,5-f)-(1,10)phenanthroline (2-HNCP) and different aromatic carboxylic acid ligands, namely, [Pb(2-NCP)(L1)]n (1), [Pb2(2-NCP)2(L2)]n·2nH2O (2), [Pb2(2-NCP)2(L2)]n (3), [Pb(2-NCP)(L3)0.5]n (4) and [Pb2(2-NCP)2(L4)]n (5), where HL1 = pyridine-4-carboxylic acid, H2L2 = 2-amino-1,4-benzenedicarboxylic acid, H2L3 = 1,4-benzenedicarboxylic acid and H2L4 = 2-hydroxy-1,4-benzenedicarboxylic acid, have been synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses and infrared spectroscopy. In 1, adjacent ladder-like chains are extended into a three-dimensional (3D) supramolecular architecture by π-π interactions. In 2, the neighboring layers are interconnected by π-π interactions to afford a 3D supramolecular architecture. 3-5 exhibit similar 3D frameworks with a Schläfli symbol of 412·63 topologies. The different auxiliary ligands and the pH value of the reaction system were discussed in regard to the formation of different structures. In addition, these five complexes present high thermal stabilities, the preferential adsorption of CO2 over N2 and excellent photocatalytic activities for dye degradation under visible light irradiation.

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