Electronic structure and optical band gap of CoFe 2 O 4 thin films

A. Ravindra (1) , P. Padhan (2, 1) , Wilfrid Prellier (2)

1 IIT Madras - Indian Institute of Technology Madras
2 CRISMAT - Laboratoire de cristallographie et sciences des matériaux

Electronic structure and optical band gap of CoFe2O4 thin films grown on (001) oriented LaAlO3 have been investigated. Surprisingly, these films show additional Raman modes at room temperature as compared to a bulk spinel structure. The splitting of Raman modes is explained by considering the short-range ordering of Co and Fe cations in octahedral site of spinel structure. In addition, an expansion of band-gap is observed with the reduction of film thickness, which is explained by the quantum size effect and misfit dislocation. Such results provide interesting insights for the growth of spinel phases.

Mots clés: Thin films; Ferromagnetic materials; Transition metal oxides; Optical absoprtion; Absorption spectroscopy; Phonons; Electronic structure; Quantum size effects; Band gap; Raman spectroscopy

Domaines: Matériaux; Chimie; Physique [physics]

A. Ravindra, P. Padhan, Wilfrid Prellier. Electronic structure and optical band gap of CoFe 2 O 4 thin films. Applied Physics Letters, 2012, 101 (16), pp.161902. ⟨10.1063/1.4759001⟩. ⟨hal-02118578⟩