[13p-D305-1~16] 9.2 Nanoparticles, Nanowires and Nanosheets

[13p-D305-11] Magnetic Moment Distribution and Magnetic Structure of Nanosized Antiferromagnetic NiO

〇Toshifumi Iimori¹, Yuya Imamoto¹, Nobuya Uchida¹, Yudai Kikuchi¹, Keita Honda¹ (1.Muroran Tech.)

Keywords:Magnetic nanoparticles, Superparamagnetism, Size effects

Nanosized antiferromagnetic materials exhibit superparamagnetism and paramagnetism, having different magnetic property to the bulk materials. It has been a key issue for the understanding of the complicated magnetic property to correctly separate a superparamagnetic component from a paramagnetic component that linearly depends on magnetic fields in the observed magnetization. Here, we report the separation of these two components observed in the magnetization of antiferromagnetic NiO nanoparticles by applying a scaling law in the magnetization of superparamagnets. The distribution of the magnetic moment was taken into account without a priori assumption of the distribution function. The magnetic moments causing superparamagnetism had a bimodal distribution with different mean values. The contribution of the two different superparamagnetic components could thus be newly clarified and was ascribed to the uncompensated spins in the core and on the surface.