Ferromagnetic ordering in half metallic Fe doped CdS diluted magnetic semiconductor: A DFT study

• Published in: Physica. B, Condensed matter Vol. 565; pp. 25 - 32
• Main Authors: Saikia, D., Jami, Junaid, Borah, J.P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.07.2019; Elsevier BV
• Subjects: Antiferromagnetism; Band structure; CdS nanoparticles; Crystallites; Density of states; Diffraction; Dilution; Ferromagnetism; Fluorescence; Iron; Magnetic semiconductors; Magnetism; Nanoparticles; Photoluminescence; Polarization (spin alignment); Quantum confinement; Semiconductors; Spectrum analysis; Transmission electron microscopy; X-ray diffraction; Zinc; Zincblende; X-ray diffraction; Band structure; Density of states; Ferromagnetism; CdS nanoparticles
• ISSN: 0921-4526; 1873-2135
• DOI: 10.1016/j.physb.2019.04.022

A detailed experimental and theoretical investigations on the origin of room temperature ferromagnetism in Fe doped CdS diluted magnetic semiconductor is reported in the present study. X-ray diffraction results reveal the cubic zinc blende CdS structure with an average crystallite size of 2 nm–3 nm which is in concurrence with the Transmission electron microscopy results. UV–visible spectroscopy depict the enhancement of optical band gap of Fe doped CdS nanoparticles compared to the bulk CdS as a result of the quantum confinement effect. Photoluminescence spectra revealed the presence of Cd2+ and S2− defect states in the nanoparticles in addition to the fluorescence quenching effect. FTIR results demonstrate the stretching vibrations of CdS bond. Magnetic study confirms the existence of room temperature ferromagnetic ordering in the nanoparticles for the lower concentration of Fe, as a result of spin polarization induced by the Fe atoms to the nearest neighboring S atoms. At higher concentration of Fe, the enhanced antiferromagnetic interaction between short range Fe ions suppresses the ferromagnetic ordering. Theoretical calculations demonstrate the half metallic nature of Fe doped CdS system with strong p-d hybridization between the Fe-d states and the S-p states which results the room temperature ferromagnetism. •DFT calculations are performed to investigate the ferromagnetic ordering in the Fe doped CdS nanoparticles.•Fe doped CdS system shows half metallic properties.•The ferromagnetic ordering is due to p-d exchange interaction between the localized d spins of the Fe ions and the free delocalized carriers.•p-d hybridization between the d states of Fe and the p states of S are observed in the Fe doped CdS system.