▎ 摘　　要

A first principle calculation has been performed to explore the magnetism in nano structures of graphene due to vacancies in carbon lattice and functionalized (hydrogenated) graphene due to vacancies in hydrogen lattice. Nano structures containing 50C atoms (5 x 5 x 1 super cell) have been considered. Using the method of numeric localized atomic orbitals, pseudo potentials and density functional theory, spin polarised electron density of states have been calculated and C-C bond lengths, C-C-C and H-C-C bond angles, formation energy and magnetic moment have been obtained. It has been found that due to defects (vacancies) in carbon lattice of pristine graphene, nano structure develops magnetic moment, which varies with the size of defect. A nano structure with four contiguous vacancies is found to have a magnetic moment of 2.0 mu(B). The nano structures of hydrogenated graphene also develop magnetic moment due to vacancies in hydrogen lattice, which varies with number and position of vacancies. A nano structure with half hydrogenated graphene obtained by removing all the hydrogen atoms from one side of graphane, (alternate vacancies in hydrogen lattice 50C25H atoms, graphone) is found to develop a large magnetic moment of 25.0 mu(B).