Work

Ferromagnetism of Nanographite Structures in Carbon Microspheres

Year: 2016

Type: article

Abstract: Carbon microspheres with unusual magnetic properties have been prepared by the method of solid-phase pyrolysis where metal-free phthalocyanine was used as a precursor. The morphology, structure, and magnetic properties of prepared samples were investigated using electron microscopy, magnetometry, and electron paramagnetic resonance. Carbon microspheres with a mean diameter d = 3.40 ± 0.15 μm consist of graphitized nanocrystallites with a thickness of 5-15 graphene layers. The samples demonstrate a strong paramagnetism with the concentration of paramagnetic centers ~5×1019spin/g. In the temperature range of 5-100 K, a ferromagnetism was revealed with a maximum value of the saturation magnetization, Ms~ 0.03 emu/g at T = 25 K. The temperature-independent diamagnetism with susceptibility of χDia= -1 × 10-6emu/g · Oe was also measured.

Source: IEEE Transactions on Magnetics

DOI: 10.1109/tmag.2016.2527792