Magnetic phase diagram, phase transitions, and cation distribution in Pb1-xBax(Fe0.5Nb0.5)O3 perovskites
Abstrakt
The 57Fe-enriched polycrystalline perovskite samples Pb1-xBax(Fe0.5Nb0.5)O3, x = 0.25, 0.5, 0.75 were prepared by a solid-state synthesis and studied in detail by X-ray powder diffraction (XRD), neutron diffraction, measurement of magnetic properties, Mo center dot ssbauer spectroscopy (MoS), and nuclear magnetic resonance (NMR) in a wide temperature range. The temperature dependences of hyperfine, structural, and magnetic parameters were obtained, with particular attention to their values during magnetic and structural transitions.
Relatively broad transitions to antiferromagnetically ordered state were observed in all samples. Ne ' el temperatures TN were determined from the MoS spectra, the spin-glass transition was deduced from the characteristic behavior of the temperature dependences of ZFC/FC susceptibilities and remanent magnetization.
Introduction of Ba into the structure gradually disrupts the long-range AFM order present in Pb(Fe0.5Nb0.5)O3, which leads to lowered TN and broadened transition. The magnetic phase diagram of Pb1-xBax(Fe0.5Nb0.5)O3 for the whole mixing interval Pb-Ba was obtained by combining the results of various methods.