Effects of Cr and SiN contents on the microstructure and magnetic grain interactions of nanocomposite FePtCr-SiN thin films
Effects of Cr and SiN contents on the microstructure and magnetic grain interactions of nanocomposite FePtCr-SiN thin films
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Cr和SiN含量对纳米复合FePtCr-SiN薄膜微观结构和磁粒相互作用的影响
DOI：
10.1109/tmag.2002.806335
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发表时间：
2003
影响因子：
2.1
通讯作者：
C. Chiang
中科院分区：
文献类型：
--
作者：
S. C. Chen;P. Kuo;A. Sun;C. Lie;C. Chiang
采用直流溅射和射频磁控溅射的方法，在自然氧化的硅衬底上制备了x=0-25at.%，/spl Delta=0-30vol.%的颗粒状纳米复合材料[(FePT)/sub100-x/-Cr/subx]/sub100-/SPL Delta//-(SiN)/subSPL Delta//薄膜。我们在600℃的真空中对沉积的薄膜进行了退火处理，然后用冰水淬火，以便将软磁面心立方/SPL伽马/-FePT相转变为硬磁面心四方/SPL伽马//亚1/-FePT相(L1/SUB 0/相)。透射电子显微镜观察表明，铬和氮化硅能够抑制磁性颗粒的生长，薄膜的结构为非磁性的氮化硅基质，其中弥散分布着FePtCr颗粒。随着铬或氮化硅含量的增加，磁性颗粒的平均尺寸减小。能谱(EDS)分析表明，铬主要存在于磁性颗粒的晶界和晶内之间的晶界区域。随着Cr或SiN含量的增加，磁性颗粒被SiN隔离，磁性颗粒相互作用减弱。增加SiN体积分数可以提高薄膜的热稳定性。我们发现，[(FePT)/sub90/-Cr/sub10/]/sub85/-(SiN)/sub15/薄膜在600/spl deg/C下热处理30min是适合于高密度磁记录的。薄膜中FePtCR的平均粒径约为9.5 nm。其面内矫顽力H/subc/为3.7Koe，饱和磁化强度M/subS/为450emu/cm/sup/3/，面内垂直度S/约为0.75。
We have fabricated granular nanocomposite [(FePt)/sub 100-x/-Cr/sub x/]/sub 100-/spl delta//-(SiN)/sub /spl delta// thin films with x=0-25 at.% and /spl delta/=0-30 vol.% on natural-oxidized silicon substrate by dc and radio-frequency magnetron cosputtering of FePt, Cr, and Si/sub 3/N/sub 4/ targets. We annealed the as-deposited film in vacuum at 600/spl deg/C and then quenched it with ice water in order to transform the soft magnetic face-centered cubic /spl gamma/-FePt phase to the hard magnetic face-centered tetragonal /spl gamma//sub 1/-FePt phase (L1/sub 0/ phase). Transmission electron microscopy observation indicated that Cr and SiN can restrain the grain growth of magnetic grains, and that the structure of the film is a nonmagnetic SiN matrix with FePtCr particles dispersed in it. Average grain size of the magnetic particles decreased as Cr or SiN content increased. Energy dispersed spectrum (EDS) analysis showed that Cr exists mainly in the grain surface area (between the grain boundary and the inner grain) of the magnetic grains. The magnetic grains are isolated by SiN and magnetic grain interactions are reduced as Cr or SiN content is increased. Increasing the SiN volume fraction increases the thermal stability of the film. We found the [(FePt)/sub 90/-Cr/sub 10/]/sub 85/-(SiN)/sub 15/ film, annealed at 600/spl deg/C for 30 min, is suitable for high-density magnetic recording. Average grain size of the FePtCr in this film is about 9.5 nm. Its in-plane coercivity H/sub c/// is 3.7 kOe, saturation magnetization M/sub s/ is 450 emu/cm/sup 3/, and in-plane squareness S/sub /// is about 0.75.