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Local structural analysis of Pb(Fe <sub/>1/2</sub> Nb <sub/>1/2</sub> )O <sub/>3</sub> multiferroic material using X-ray fluorescence holography
摘要： We performed X-ray fluorescence holography measurements on a Pb(Fe1/2Nb1/2)O3 (PFN) multiferroic material in order to investigate the temperature dependence of three dimensional local structure around Fe atoms. It was found that the atomic image intensity of the nearest neighbor Pb atom abruptly decreases when the temperature becomes lower than the Néel temperature (TN) of about 150 K, while the intensity of the atomic image at nearest Fe/Nb position remains almost unchanged. These observations show that the magnetic transition at TN induces static positional shifts of Pb atoms but does not strongly influence the Fe/Nb atoms, which suggests the involvement of Pb ions into the superexchange interaction between Fe ions and its contribution to the spin-lattice coupling in PFN.
关键词： Pb(Fe1/2Nb1/2)O3,local structure,X-ray fluorescence holography,multiferroic material,temperature dependence
更新于2025-09-19 17:13:59
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Dielectric, electrical and impedance study of single perovskite Pb(Ni1/3Mn1/3W1/3)O3
摘要： A multiferroic material Pb(Ni1/3Mn1/3W1/3)O3 with ferroelectric and ferromagnetic properties at room temperature is designed for multifunctional applications. A orthorhombic perovskite crystal structure has been assigned for the present perovskite according to the X-ray diffraction patterns. At 1 kHz, dielectric constant (er) increases from 1655 at 298 K to its ?rst maximum 3514 at 457 K referred as magnetic transition. The high values of er in the low frequency range show better dispersion, and with the increase in frequency, a gradual decrease in the er values was observed. The contribution of grain and/or electrode/interface effects in the resistive/capacitive properties was ascertained by the Nyquist plots. An equivalent circuit has been suggested consisting of resistive and capacitive components (R, C, Q) estimates the bulk (grain) and grain boundary resistance and capacitance. The activation energy was found to be greater than 0.2 eV, supporting the conduction mechanism due to hopping of charge carriers.
关键词： Solid-state reaction,Multiferroic material,Dielectric response,Electrochemical impedance spectroscopy,Ceramics
更新于2025-09-09 09:28:46