A novel hexagonal YFeO3 3D nanomaterial with room temperature ferromagnetic properties prepared by self-assembling method
Yi Sui, Fei Lu, Xiaoyu Liu, Yingde Zhang, Xiaohua Sun, Changsheng Liu
Abstract
In this study, a novel hexagonal-YFeO3 (abbreviated as h-YFeO3) nanomaterial with stable room temperature ferromagnetic properties was synthesized by a two-step self-assembly approach. This nanomaterial with three-dimensional (abbreviated as 3D) frame architecture is homogeneously assembled by h-YFeO3 nanocrystalline with a diameter around 10–20 nm. As the annealing temperature rose from 823 K to 923 K, the structure of YFeO3 transformed from amorphous phase to P63/mmc hexagonal crystal type during the self-assembly process due to the combustion of urea, while P63cm type crystal generated at 873 K. The magnetic hysteresis loops recorded by vibrating sample magnetometry at 273–303 K, which displayed a transition from antiferromagnetic (paramagnetic) to ferromagnetic order. This ferromagnetic behavior related to the violation in inversion symmetry of hexagonal YFeO3 structure, causing by a greater distortion in nanocrystal boundary of perovskite-like structure and an increase in asymmetric covalent Y–O bonding. The ferromagnetic properties of h-YFeO3 3D nanomaterial were tested and found to be stable at room temperature (273 K–303 K), with maximum magnetization (Mm) value of h-YFeO3 3D nanomaterial reaching 2.6 A m2/g, 11 times higher than YFeO3 nanoparticle (20–50 nm). In sum, these findings look promising for future large-scale production of the advanced and inexpensive ferromagnetic perovskite-structure materials at room temperature as well as in magnetic application.