Room temperature multiferroic $Ba4Bi2Fe2Nb8O30$⁠: Structural, dielectric, and magnetic properties Available to Purchase

A room temperature multiferroic compound $Ba4Bi2Fe2Nb8O30$ was synthesized using a solid state reaction technique. Rietveld analysis of x-ray diffraction data shows that $Ba4Bi2Fe2Nb8O30$ has a tetragonal (space group $P4bm$⁠) tungsten bronze structure. In this structure, the $Fe3+$ and $Nb5+$ statistically occupy the octahedral center while the $Ba2+$ ions and the $Bi3+$ ions occupy the pentagonal channels and the square channels, respectively. Diffuse dielectric peaks with strong frequency dispersion in the temperature range from 150 to 300 K can be attributed to the random distribution of $Fe3+$ and $Nb5+$ at B sites. Magnetic hysteresis loop at room temperature is also obtained, which suggests that $Ba4Bi2Fe2Nb8O30$ is a room temperature multiferroic compound. The coupling between the relaxor behavior and magnetic ordering is verified by observing an increase of magnetization near the maximum dielectric constant temperature.