Lead-free (K, Na, Li) NbO3/NiFe2O4 thin films by pulsed laser deposition: Structure, dielectric, magnetic and magnetodielectric behavior

In this paper we propose the fabrication of eco-friendly (1-x) (K, Na, Li) NbO3-xNiFe(2)O(4) (KNNL-NFO) thin films on Pt/Si substrate with (x = 0.01, 0.02, 0.03, and 0.04) as target source by Pulsed Laser Deposition (PLD) technique. Structural analysis carried out by X-ray diffraction and Raman spectroscopy method confirmed the perovskite phase of KNNL and ferrite phase for NFO of the composite films. Chemical state evaluated by X-ray photoelectron spectroscopy confirmed the presence of Fe3+ along with minor Fe 2+ ions. These films exhibit a clear magnetic hysteresis behavior and with increasing ferrite composition the saturation magnetization increases and sufficiently large room temperature magnetodielectric (MD) constant with low losses are obtained. Exchange between thermally activated charge carriers created by hole-electron pair in d-orbital satisfying Maxwell-Wagner polarization was observed during room temperature dielectric permittivity measurements. All the composite films exhibit poor saturation polarization and leakage current was found to be decrease with increasing ferrite composition. Ac conductivity plot infers hopping mechanism to be responsible for the conduction process obeying Jonscher's power law. (C) 2019 Elsevier B.V. All rights reserved.