Magnetron sputtering deposition of [FePt/Ag]n multilayers for perpendicular recording

[FePt/Ag]n multilayers were deposited on glass substrates by RF magnetron sputtering and ex situ annealed at 550℃ for 30 min. The effects of inserted Ag layer thickness and the number of bilayer repetitions （n） on the structure and magnetic properties of the multilayers were investigated. It was found that the difference between in-plane and out-of-plane coercivities varied with an increase of inserted Ag layer thickness in the [FePt 2 nm/Ag x nm]10 multilayers. The ratio of out-of-plane coercivity to in-plane coercivity reached the maximum value with the Ag layer thickness of 5 nm, indicating that the Ag layer thickness plays an important role in obtaining perpendicular orientation. For the [FePt 2 nm/Ag 5 um]n multilayers, perpendicular orientation is also influenced by n. The maximum value of the ratio of out-of-plane coercivity to in-plane coercivity appeared when n was given as 8. It was found that the [FePt 2 nm/Ag 5 nm]8 had a high perpendicular coercivity of 520 kA/m and a low in-plane one of 88 kA/m, which shows a strong perpendicular anisotropy.     

SmCo／Cr薄膜中Cr底层最佳溅射条件的正交设计研究

在SmCo/Cr薄膜中，Cr底层的取向结构对薄膜的磁学性能有很大的影响。设计了4因素3水平的正交实验L9(3^4)，并通过数理统计的方法分析了Cr底层的溅射参数对SmCo／Cr薄膜矫顽力的影响。用较少的实验得到Cr底层的最佳实验条件：靶基距为4cm，功率为50w，溅射气压为0．5Pa，溅射时间为9min。并发现了靶基距、功率和溅射气压对薄膜矫顽力的影响较大，其中靶基距是薄膜矫顽力最主要的控制因素。而溅射时间在所取的水平上对薄膜矫顽力的影响最小。本实验设计可达到95％的置信度。     

Nd含量对高Zr含量纳米双相NdxFe90.5-xZr3.0B6.5合金微结构和磁性能的影响

采用电弧炉快淬和晶化退火工艺制备高性能NdxFe90.5-xZr3.0B6.5（F8．5=11．5）快淬磁体。结果表明，Zr的添加显著提高磁体的磁性能，Nd含量可以明显提高磁体的磁性能，X由8．5增加到10．5时，NdxFe90.5-xZr3.0B6.5磁体的磁能积由75kJ／m^3升高到114kJ／m^3，接近于美国Magnequench公司的MQP-B磁粉性能。     

Cr底层中添加Ti对SmCo薄膜磁学性能的影响

采用直流磁控溅射法制备了SmCo/Cr,SmCo/CrTi 和SmCo/CrTi/Cr 系列薄膜。SmCo 薄膜的XRD 结果表明:在Cr 底层中添加Ti,得到的CrTi,CrTi/Cr 底层也是以(110)面择优取向的,但是和Cr 底层相比,衍射峰的位置由44.39°偏移到44.19°。薄膜的磁学性能由振动样品磁强计(VSM)测定,分析VSM 的测量结果可知,用CrTi 和CrTi/Cr做底层,SmCo 薄膜的矫顽力Hc、矩形比S、矫顽力矩形比S*的值都比Cr 底层的大,并且磁反转体积V*的值比Cr 底层的小。SmCo 薄膜的δM(H)曲线说明,Cr 做底层时,薄膜晶粒间的相互作用为极化作用,CrTi,CrTi/Cr 做底层时,薄膜晶粒间的相互作用为交换耦合相互作用。     

甩带处理TbMn6Sn6化合物的磁性研究

研究了甩带速度对TbMn6Sn6化合物晶体结构和磁性的影响。结果表明,甩带冷却速度对TbMn6Sn6化合物的晶体结构几乎没有影响,主要是由1：6：6型相所构成,其中含有少量铁磁性的Mn3Sn2杂相;随着甩带速度从3900r／min降至1500r／min,试样晶粒尺寸依次为220、170、280和340nm;甩带冷却速度对TbMn6Sn6化合物的室温矫顽力几乎没有影响,以3900r／min甩带制成的TbMn6Sn6化合物的矫顽力,随着温度的升高,从5K下的1600 Oe上升至100K下的11360Oe,然后随着温度继续上升至300K,其矫顽力减小至533Oe。     

Effect of Ti layer thickness on microstructure and magnetic properties of Ti/Co/Ti films

TiCoTi granular films were prepared by DC facing-target magnetron sputtering system onto glass substrates and subsequently in situ annealing in vacuum. Structural of Ti ( t nm)/Co (40 nm)/Ti ( t nm) films were investigated in detail, which shows that the majority Co nanograins are formed as the hexagonal-close-packed (HCP) structure. Vibrating sample magnetometer (VSM) and scanning probe microscope (SPM) were applied to study the magnetic properties, morphologies and domain structures of these samples. It has been found that the structure and magnetic properties of the Ti/Co/Ti films depend strongly on the Ti layer thickness. The out-of-plane coercivities ( Hc) of the film is maximum about 78.8 kA·m-1 when t =5 nm with annealing at 300 ℃; the distributing of grains of the sample is uniformity; and the average size of particles is about 13 nm. The obtained results suggest that this system is perpendicular anisotropy and might be applicable to perpendicular magnetic recording media.     

高导磁纳米晶Fe67.9Cu0.5 Nb0.6Cr3V1Si14B13合金的高频磁性能

报道了新开发的纳米晶Fe67.9Cu0.5Nb0.6Cr3V1Si14B13合金的综合磁性能.新合金的直流起始磁导率和矫顽力水平分别为7.8×104和0.8Am-1.在Bm=0.3T,f=100kHz和Bm=0.2T,f=200kHz条件下,铁损分别为544kW·m-3和830kW·m-3,这可与纳米晶Fe73.5Cu1Nb3Si13.5B9的相比,但比优良的功率Mn-Zn铁氧体H7c4的低得多.在直到1MHz的频率范围内考查了弱场磁导率的频散特性.在f=20～103kHz和Bm=0.01～1.0T范围内,考查了高频矫顽力和Bm的关系.在f=20～103kHz和Bm=0.05～0.9T范围内,描述了铁损和f及Bm的关系.     

Effect of Ag（Ti） underlayers on CoCrPt thin film media

1　INTRODUCTIONMany works have been done in recent years onCo based granular alloys for potential applicationsas recording magnetic media[1 5]. The ideal granu lar media should consist of small and uniformgrains. High anisotropy magnetic grains embeddedin a robust non magnetic matrix are required. Highcoercivity, large squareness and negative nuclea tion field are very important for magnetic recordingfilms.The addition of Pt to the recording layer canincrease the anisotrop…     

INFLECTION OF COERCIVITY DURING LOCAL CRYSTALLIZATION OF Fe-Si-B AMORPHOUS ALLOYS

An inflection hehaviour was revealed during isothermal annealing under the observation oftransition of the coercivity of Fe-Si-B amorphous alloys during local crystallization.It maybe interpreted by the transition of α-Fe grain precipitated from single to multiple domain,Thus,the theoretical expression of H_0-t_a may be derived.The plot of expression H_0-t_a calcu-lated well represents the feature of the experimental curve.     

各向同性富铁Fe—Pt纳米晶薄膜的形成及其磁性

采用直流溅射多层结合退火技术，制备了不同富铁量的各向同性Fe－Pt纳米晶永磁薄膜。对这些永磁薄膜的研究表明：在500℃退火3min－10min得到的所有不同富Fe量的Fe－Pt永磁薄膜是各向同性的；它们的磁滞回线都显现单相的硬磁行为；所有的薄膜显示出剩磁增强效应，其剩磁随富Fe含量的增加而增大。磁力显微镜观测表明，在热退磁状态下Fe－Pt薄膜显现出不规则的模跨数个晶凿的岛状畴，其大小是平均晶粒尺寸的7倍－10倍。