Bismuth-Doped Nickel Ferrite Nanoparticles for Room Temperature Memory Devices

Searching for materials and creating promising functionalities are the main driving force behind most of the studies in the area of materials science and condensed matter physics. The development of advanced multiferroic materials by utilizing the phenomenon of magnetodielectric effect provides great prominence toward the fabrication of next-generation nonvolatile memory devices. We have observed a multiferroic property at room temperature for the first time in sol-gel-derived nanocrystalline bismuth-doped nickel ferrite. Nickel ferrite, although owning traditional ferrimagnetism as observed from the magnetization study, a perfect ferroelectric polarization hysteresis loop with reasonably high polarization (10 μC/cm²), and a room temperature magnetodielectric constant of 2.8%, has been achieved at room temperature by bismuth doping. This finding is quite fascinating toward the search of multiferroic materials, which deserves further theoretical and experimental studies to pin down the exact origin of polarization in this spinel ferrite. Because of room temperature multiferroicity, bismuth-doped nickel ferrite could be a superior alternative multiferroic material in the near future for the fabrication of next-generation nonvolatile memory devices.