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具有条纹磁畴结构的磁性薄膜表现出面内转动磁各向异性,对于解决高频电子器件的方向性问题起着至关重要的作用.本文采用射频磁控溅射的方法,研究了NiFe薄膜的厚度、溅射功率密度、溅射气压等制备工艺参数对条纹磁畴结构、面内静态磁各向异性、面内转动磁各向异性、垂直磁各向异性的影响规律.研究发现,在功率密度15.6 W/cm~2与溅射气压2 mTorr(1 Torr=1.33322×102Pa)下生长的NiFe薄膜,表现出条纹磁畴的临界厚度在250 nm到300 nm之间.厚度为300 nm的薄膜比250 nm薄膜的垂直磁各向异性场增大近一倍,从而磁矩偏离膜面形成条纹磁畴结构,并表现出面内转动磁各向异性.高溅射功率密度可以降低薄膜出现条纹磁畴的临界厚度.在相同功率密度15.6 W/cm~2下生长300 nm的NiFe薄膜,随着溅射气压由2 mTorr增大到9 mTorr,NiFe薄膜的垂直磁各向异性场逐渐由1247.8 Oe(1 Oe=79.5775 A/m)增大到3248.0 Oe,面内转动磁各向异性场由72.5 Oe增大到141.9 Oe,条纹磁畴周期从0.53μm单调减小到0.24μm.NiFe薄膜的断面结构表明柱状晶的形成是表现出条纹磁畴结构的本质原因,高功率密度下低溅射气压有利于柱状晶结构的形成,表现出规整的条纹磁畴结构,高溅射气压会导致柱状晶纤细化,面内转动磁各向异性与面外垂直磁各向异性增强,条纹磁畴结构变得混乱.
The magnetic thin film with striped magnetic domain structure exhibits magnetic anisotropy in plane and plays a crucial role in solving the directivity problems of high frequency electronic devices.In this paper, the RF magnetron sputtering method is used to study the magnetic properties of NiFe thin films Thickness, sputtering power density, sputtering pressure and other preparation process parameters on the stripe domain structure, in-plane static magnetic anisotropy, in-plane rotational magnetic anisotropy and perpendicular magnetic anisotropy were studied.It was found that at power NiFe films grown at a density of 15.6 W / cm 2 and a sputtering pressure of 2 mTorr (1 Torr = 1.33322 × 102 Pa) show that the critical thickness of striped magnetic domains is between 250 nm and 300 nm. A thin film with a thickness of 300 nm The magnetic anisotropy field nearly doubled than that of 250 nm film, and the magnetic moment deviated from the film surface to form the stripe magnetic domain structure and showed the in-plane magnetic anisotropy of rotation. High sputtering power density can reduce the stripe magnetic film The critical thickness of the NiFe thin films grown at 300 nm with the same power density of 15.6 W / cm ~ 2 increased with increasing sputtering pressure from 2 mTorr to 9 mTorr. The vertical magnetic anisotropy field of NiFe films gradually increased from 1247.8 Oe (1 Oe = 79.5775 A / m) to 32 48.0 Oe, the in-plane rotational magnetic anisotropy field increases from 72.5 Oe to 141.9 Oe, and the periodicity of striped magnetic domains monotonically decreases from 0.53μm to 0.24μm. The cross-sectional structure of NiFe films shows that the formation of columnar crystals is stripe domain The nature of the structure, the low sputtering pressure at high power density is conducive to the formation of columnar crystal structure, showing a regular striped magnetic domain structure, high sputtering pressure will lead to columnar grain refinement, in-plane rotational magnetic anisotropy and surface Outer perpendicular magnetic anisotropy increases, stripe domain structure becomes chaotic.