Optimizing the physical properties of calcium nanoferrites to be suitable in many applications

Calcium nano ferrite with composition CaGdxEryFe2−x−yO4 (x = y = 0.0, x = 0.025, y = 0.05) was prepared by citrate gel auto combustion method. The prepared samples showed orthorhombic phase structure and the crystallite sizes were found in the range of 32.1–35.3 nm. Detailed observation via the Field Emission Scanning Electron Microscopy (FESEM) showed that the calcium ferrite nano-particles were spherical and capsule like formation shape. The hysteresis loop confirms the magnetic behavior of the investigated samples, which is then discussed on the basis of super exchange interactions. Magnetic parameters such as saturation magnetization, coercivity, and retentivity were obtained. Greater than six-fold increase in coercivity (≈2085 Oe) was observed in calcium nanoferrites compared to the doped samples (≈360 Oe). The CaFe2O4-type structure includes edge- and corner sharing BO6 octahedral, constituting a very unique network similar to perovskite-related nanoparticles. This structural network leads to an improvement in the physical properties of the investigated samples. Great efforts have been made to synthesize pure nanoferrite samples without any secondary phases even after the substitution of low soluble rare earth ions. Special attention should be given to calcium ferrite nanoparticles which are suitable candidates to be used in the manufacturing of bone-like scaffolds, hyperthermia treatment of cancer and biological activity.