First principles insight into magnetic and optoelectronic properties of Ni doped KNbO3 perovskite

Abstract

The future technologies belong to the spin-based electronics (called spintronics) which is considered as highly efficient and quick response device with advanced functionalities. In order to develop a functional spintronic device, it is pertinent to control the spin currents and readout of their magnetic states which exemplify the importance of presented study. Herein, physical properties of KNbO 3 are engineered via concentration dependent Ni doping with dopant’s concentration of 12.5%, 25%, 50%, and 75%. Ferromagnetic character is obtained along with spin polarized bands and DOS structures. Further analysis of projected DOS reveals the Ni-d based metallic character in spin down channel along with semiconductive nature in spin up version, translating the considered doped systems into half metallic ferromagnetic (HMFM) materials. The computed HM direct gaps are 0.956, 0.957, 1.040 and 0.876 eV for K 0.875 Ni 0.125 NbO 3 , K 0.75 Ni 0.25 NbO 3 , K 0.5 Ni 0.5 NbO 3 , and K 0.25 Ni 0.75 NbO 3 , respectively. The magnetic moment values obtained for K 0.875 Ni 0.125 NbO 3 , K 0.75 Ni 0.25 NbO 3 , K 0.5 Ni 0.5 NbO 3 , and K 0.25 Ni 0.75 NbO 3 , are 1.00153, 1.00003, 1.02449, and 1.04210 μ B per formula unit, respectively. The determined magnetic moment values illustrate the ferromagnetism in studied Ni modified KNbO 3 , perovskites, which is originated from Ni and minor contribution of O ions. Further, optical response of Ni doped KNbO 3 is studied which show UV region of light as a strong absorbing region. The presented results predict the suitability of considered material in various optical filters and spintronic devices.