Modulation of ferromagnetism and transport in B_xC_yN_z thin films via nitrogen doping and defects

摘要

Thin films of BxCyNz are grown for the first time using the ammonia assisted Pulsed Laser Deposition (PLD) technique, known for its precise stoichiometry control, and their magnetic and transport properties are carefully studied along with atomistic chemical and microstructural details by using the techniques of X-ray photoelectron spectroscopy (XPS), Raman Spectroscopy and synchrotron-based X-ray absorption near-edge structure (XANES) and Valence Band Spectroscopy (VBS). The role of dopants and defects is brought out using a combined comprehensive analysis based on these experimental results and Density Functional Theory (DFT) calculations. An interesting crossover is noted in the transport mechanism of charge carriers with the change in doping level of specific nitrogen defects. A robust and high saturation magnetization is achieved in BCN films which is higher by almost hundred times as compared to that in similarly grown undoped carbon film.