title: Pronounced multiferroicity in oleic acid stabilized BiFeO3 nanocrystals at room temperature.
abstract: We report on the experimental observation of pronounced multiferroicity in BiFeO3 nanocrystals (size approximately 40 nm) at room temperature. Large scale BiFeO3 nanocrystals are synthesized using a low temperature chemical route and further stabilized with oleic acid. The nanocrystals exhibit a significant distortion in lattice parameter c compared to the bulk. Oleic acid plays an important role in reducing oxygen vacancies and Fe2+ ions at the nanocrystal surface giving rise to a high resistivity (approximately 10(10) omega-cm at 300 K) of the sample. The direct band gap of nanocrystals is measured to be approximately 4.2 eV (about 1.5 times the bulk value) suggesting a strong quantum confinement effect. The nanocrystals show a remarkably high spontaneous saturation magnetization approximately 4.39 emu/g along with a prominent ferroelectric hysteresis loop at room temperature. Particle size effect leading to the appearance of large number of uncompensated spins and suppression of modulated spin structure have resulted a strong spontaneous magnetization in such nanoscale multiferroic materials.
authors.affiliation: Department of Physics, Visva-Bharati, Santiniketan 731235, India.
authors.forename: Dabbugalla
authors.initials: D
authors.lastname: Mahesh
authors.forename: Swapan K
authors.initials: SK
authors.lastname: Mandal
authors.forename: Bipul K
authors.initials: BK
authors.lastname: Mahato
authors.forename: Bivas
authors.initials: B
authors.lastname: Rana
authors.forename: Anjan
authors.initials: A
authors.lastname: Barman