运用电位置换结合化学还原方法制备了两种不同结构的CoPt纳米棒材料,一种为实心结构(CoPt-a),一种为空心结构(CoPt-b).采用透射电镜(TEM)和能量散射光谱(EDS)研究了其形貌和组成.在5和300K下测试了两种纳米棒的磁学性能.结果显示,CoPt-a和CoPt-b纳米棒在5K时的矫顽力分别为6.5和9.3A·m-1,温度升至300K时,两种结构CoPt纳米棒矫顽力均减小为0A·m-1.场冷曲线(FC)和零场冷曲线(ZFC)结果表明两种结构的CoPt纳米棒均表现出超顺磁性,阻塞温度(TB)分别为10.0和9.0K.两种CoPt纳米棒组成、结构等不同可能是引起其矫顽力、磁化强度和阻塞温度差异的主要原因.
We prepared two kinds of CoPt nanorods by galvanic displacement reaction and chemical reduction. One type was solid (CoPt a) and the other was hollow (CoPt b). Transmission electron microscopy (TEM) and energy dispersive X ray spectroscopy (EDS) were used to characterize the shape and composition of the nanorods. The magnetic properties were measured at 5 and 300 K. The coercivities of the CoPt a and CoPt b nanorods were found to be 6.5 and 9.3 A· m-1 at 5 K, respectively. The coercivities decreased to 0 A· m-1 when the temperature was increased to 300 K. The field cooling (FC) and zero field cooling (ZFC) curves indicated that both the CoPt a and CoPt b nanorods are superparamagnetic. The blocking temperatures (TB) of CoPt a and CoPt b are 10.0 and 9.0 K, respectively. The different magnetic properties of the two kinds of CoPt nanorods including coercivity, magnetization, and blocking temperature may be due to their different compositions and structures.