铁磁性坡莫合金纳米环的制备与磁性研究

Preparation and Magnetic Properties of Ferromagnetic Permalloy Nanorings

铁磁性纳米环是一种纳米尺寸的环状实体,由于具备高密度磁存储的能力,被认为是下一代高性能存储器——磁随机存储器(MRAM)的重要结构单元。利用聚苯乙烯微球模板法制备了单分散的坡莫合金Ni75Fe25(NiFe)纳米环,并用扫描电子显微镜(SEM)表征了纳米环的分布情况;用振动样品磁强计(VSM)测量了NiFe纳米环的磁化曲线,显示出两种磁状态,即涡旋态(Vortex state)和双畴态(Onion state),并利用OOMMF软件对NiFe纳米环的磁化翻转过程进行微磁模拟,观察到纳米环不同磁化状态下的自旋组态。

Ferromagnetic nanoring is a ring entity, which is considered to be the elementary unit tor the next generation of high-performance memory, i.e. magnetic random access memory （MR AM）. Permalloy Ni75 Fe2s （NiFe） nanorings were fabricated by polystyrene nanosphere template, characterized by scanning electron microscopy （SEM）. The magnetic hysteresis loops were measured by using vibrating sample magnetometer, which show that there are two magnetic states： vortex and onion state. And the magnetic properties of NiFe nanorings were studied by micromagne- tic simulation with OOMMF. The spin configurations of different magnetic states were obtained by calculation.