Effect of size, phase fraction and interface coupling on the magnetic behavior of al-modified α-Fe2O3/NiFe2O4 core–shell structure

Abstract

The effect of Al doping on the NiFe 2 O 4 phase for the enhanced magnetic properties of α-Fe 2 O 3 /NiFe 2 O 4 composite has been reported. The crystalline quality of the samples improves significantly with increasing Al doping concentration. The formation of core-shell structure in the samples along with the reduction in shell thickness with Al doping has been evidenced through morphological characterization. All the samples show the optical band gap value of 1.7 eV that could produce higher efficiency toward the visible light absorption. All the samples show the doubly inverted structure (T N > T c ). The low saturation magnetization and high coercivity in the Al-doped samples in comparison with the un-doped sample are observed because of the paramagnetic spin configuration of Al ions and interface coupling between α-Fe 2 O 3 and NiFe 2 O 4 phases. The different exchange coupling in Al-modified α-Fe 2 O 3 /NiFe 2 O 4 composite systems could be associated with the NiFe 2 O 4 phase. The occurrence of narrow band gap, ferromagnetism, loop shift, freezing temperature and doubly inverted structure in the nanocomposite samples could be beneficial for photo-electrochemical water splitting, photo-catalyst and magnetic memory device applications. KeywordsNanocomposite • NiFe 2 O 4 • Core-shell structure • Exchange bias • Doubly inverted structure * P. Mallick

Effects of axial pressure on the evolution of core–shell heterogeneous structures and magnetic properties of Fe–Si soft magnetic powder cores during hot-press sintering

“…Soft magnetic powder cores (SMPCs) can enable the miniaturisation and diversification of electromagnetic devices, exhibit low eddy current loss under a wide frequency range and fill the application gap between silicon–steel and ferrite electromagnets. 2 Thus, SMPCs are promising candidates for efficient and lightweight electromagnetic devices.…”