tailieunhanh - Báo cáo hóa học: " Wet chemical synthesis and magnetic properties of single crystal Co nanochains with surface amorphous passivation Co layers"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Wet chemical synthesis and magnetic properties of single crystal Co nanochains with surface amorphous passivation Co layers | Zhou et al. Nanoscale Research Letters 2011 6 285 http content 6 1 285 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Wet chemical synthesis and magnetic properties of single crystal Co nanochains with surface amorphous passivation Co layers Shao-Min Zhou Shi-Yun Lou Yong-Qiang Wang Xi-Liang Chen Li-Sheng Liu and Hong-Lei Yuan Abstract In this study for the first time high-yield chain-like one-dimensional 1D Co nanostructures without any impurity have been produced by means of a solution dispersion approach under permanent-magnet. Size morphology component and structure of the as-made samples have been confirmed by several techniques and nanochains NCs with diameter of approximately 60 nm consisting of single-crystalline Co and amorphous Co-capped layer about 3 nm have been materialized. The as-synthesized Co samples do not include any other adulterants. The high-quality NC growth mechanism is proposed to be driven by magnetostatic interaction because NC can be reorganized under a weak magnetic field. Room-temperature-enhanced coercivity of NCs was observed which is considered to have potential applications in spin filtering high density magnetic recording and nanosensors. PACS . Introduction In the last decade diverse technological applications of magnetic nanostructures in magnetofluid recording tape flexible disk recording media permanent magnets microwave oscillators as well as biomedical materials and catalysts have provided an impetus for extensive research in nanometer scale magnets 1-17 . Most of these applications rely on the stability of ferromagnetic ordering with temperature. In nanometer scale magnets the thermal fluctuations randomize the magnetic moment by overcoming the anisotropy energy leading to unstable state of paramagnetism non-magnetic materials or superparamagnetism corresponding coercivity and hysteresis fall to zero . Cobalt Co is superior to other .