双层耦合膜的磁光克尔效应研究

稀土-过渡族金属(RE-TM)非晶垂直磁化膜用于磁光记录材料已被广泛研究。为了提高材料的读出性能,提高分辨率,降低误码率,希望材料有较大的磁光克尔旋转角θ_k。本文采用磁光双层膜耦合结构,将信息的记录和读出分别由记录层(Storage Layer)薄膜和读出层(Readout Layer)薄膜完成,将磁光克尔旋转角θ_k由单层膜的小于0.30°,提高到双层膜的0.38°,较好地解决了这一问题。     

Ag底层对TbFeCo薄膜磁性能的影响

采用射频磁控溅射法在玻璃基片上制备了TbFeCo/Ag非晶垂直磁化膜，研究了Ag底层厚度对TbFeCo薄膜磁性能的影响。原子力显微镜、振动样品磁强计与磁光盘测试仪测量结果表明：薄的银底层具有较高的表面粗糙度可以显著增大TbFeCo薄膜的矫顽力，改善TbFeCo薄膜的磁光温度特性，该薄膜有望用作高密度垂直记录介质与光磁混合记录介质。     

溅射工艺条件对TbFeCo/Pt薄膜磁性能的影响

采用射频磁控溅射法在玻璃基片上成功制得了TbFeCo/Pt非晶垂直磁化膜,系统研究了溅射工艺参数对TbFeCo薄膜磁性能的影响.振动样品磁强计测量结果表明:Tb含量在补偿成分点附近,采用较低的溅射氩气压与Pt底层,有利于提高TbFeCo薄膜的磁性能;当Tb含量为0.24,溅射功率为300W,溅射气压为0.53Pa,薄膜厚度为140nm时,TbFeCo/Pt薄膜矫顽力达到476kA/m,饱和磁化强度为151kA/m,剩磁矩形比超过0.8,该薄膜有望用作高密度光磁混合记录介质.     

电介质保护膜对磁光记录膜的磁和磁光特性的影响

采用射频磁控溅射法制备了非晶TbFeCo薄膜及其保护层AlN薄膜 ,并研究保护层对薄膜的磁和磁光特性的影响。结果表明 ,AlN薄膜可以增强薄膜磁光效应 ,同时 ,AlN薄膜对TbFeCo磁光薄膜的矫顽力、垂直磁各向异性以及本征克尔角都有一定的影响。其原因来自于溅射过程中N和Al原子对TbFeCo薄膜表面的轰击而导致的界面特性的改变     

电介质保护膜对磁光记录膜的磁和磁光特性的影响

采用射频磁控溅射法制备了非晶TbFeCo薄膜及其保护层AlN薄膜，并研究保护层对薄膜的磁和磁光特性的影响。结果表明，AlN薄膜可以增强薄膜磁光效应，同时，AlN薄膜对TbFeCo磁光薄膜的矫顽力、垂直磁各向异性以及本征克尔角都有一定的影响。其原因来自于溅射过程中N和Al原子对TbFeCo薄膜表面的轰击而导致的界面特性的改变。     

Sol-gel法制备(BiAl)DyIG石榴石磁光记录薄膜

采用柠檬酸络合物型溶胶 凝胶法首次制备得到了具有垂直各向异性的(BiAl)DyIG石榴石磁光记录薄膜,并对材料结构和磁光性质进行了研究,结果得到石榴石磁光记录薄膜磁滞回线具有较好的矩形比,在430nm和520nm的品质因子为2°和1.5°,最佳晶化温度为675℃。     

SmDyFeCo磁光薄膜的磁特性研究

采用射频磁控溅射方法制备了ＳｍＤｙＦｅＣｏ非晶磁光薄膜，研究了氩气压，溅射功率对ＳｍＤｙＦｅＣｏ薄膜磁特性的影响。实验表明，和ＤｙＦｅＣｏ非晶薄膜相比，ＳｍＤｙＦｅＣｏ非晶薄膜的矫顽力Ｈｃ随温度变化更为缓慢，并且具有更大的垂直磁各向异性常数，因而具有更好的记录特性，本征磁光克尔角可达０．３１，可以作为一种实用化的磁光记录介质。     

钡铁氧体垂直磁化膜磁各向异性研究

钡铁氧体垂直磁化膜可用作高密度磁记录介质。本文研究用低温ＲＦ磁控溅射法制备非晶薄膜，经晶化处理所得到的垂直磁化膜的饱和磁化强度Ｍｓ、矫顽力Ｈｃ及垂直磁各向异性常数Ｋｕｌ、Ｋｕ２与退火温度Ｔ的关系，并对所呈现出的变化规律作了简单解释。介绍了依据转矩曲线的形状来判断薄膜垂直性优劣的方法，从转矩曲线出发，探讨了影响薄膜磁各向异性的因素。     

磁控溅射制备TbFeCo薄膜及其光学和磁光性质研究

采用放电等离子烧结(SPS)TbFeCo合金靶,分别在Si衬底和K9玻璃衬底上磁控溅射制备了磁光薄膜TbFeCo/Si和TbFeCo/K9;利用扫描型可变入射角全自动椭偏仪,室温下测量了复介电常数谱,测量结果表明两样品介电函数值有较大差异,说明衬底对薄膜的光学性质有重要影响.用磁光Kerr谱仪,在室温下分别测量了TbFeCo薄膜的极向Kerr回线和横向Kerr回线,发现所制备TbFeCo薄膜不具有垂直磁化性质,而呈现出面内磁化性质.     

超高密度磁存储的展望

磁性存储是最常用的海量存储技术,其记录密度越来越高,发展也越来越快。本文通过对信息记录、读出和存储三个过程的分析,对比了硬磁盘记录、垂直磁记录和磁光记录的优缺点,指出了采用垂直记录模式、非晶结构合金薄膜或铁氧体薄膜介质是实现超高密记录的方向,光辅助磁记录是很有希望的记录技术。同时,还指出量子磁盘技术是未来高密记录的方向。     

Ce掺杂对TbFeCo材料磁光性能影响的研究

采用射频磁控溅射方法制备了TbFeCo非晶磁光薄膜，并在TbFeCo中引入轻稀土元素Ce，测试了薄膜的磁光性能。研究了薄膜成分对其磁光性能的影响。结果表明；在TbFeCo薄膜中掺入少量Ce时，薄膜的磁光克尔角及矫顽力都有所提高，矩形度也增加了。但随Ce掺入量的增加，薄膜的磁光性能发生恶化，较好的掺杂在10.31?左右。     

Study on Micro-magnetic Simulation of Magnetic State of TbFeCo/Anodized Aluminum Oxide Film

Based on the experimental study of the AAO underlayer??s effect on the magnetic properties and structure, combining micro-magnetic theory as well, TbFeCo/AAO film magnetic properties and magnetic reversal characteristics were analyzed by finite-element micro-magnetic calculation software Magpar. With limited hardware conditions for the computer, a TbFeCo perpendicular magnetization films model with 9×9 matrix particles was simulated. It was found that for the pinning effect of non-magnetic porous AAO barrier film on TbFeCo particle film, the coercivity of isolated TbFeCo/AAO film (2100 kA/m) was larger than the coercivity of continuous TbFeCo film (2000 kA/m). The exchange coupling among the film particles, which was affected by AAO barrier film, led to a longer magnetization reversal time of isolated TbFeCo films than that of continuous ones.     

Compositional dependence of magnetoresistance in TbFeCo amorphous film

The dependence of Tb and Co concentration on the magnetoresistance (MR) of TbFeCo amorphous films with perpendicular magnetic anisotropy have been studied at room temperature. Tb/sub x/Fe/sub (88-x-y)/Co/sub y/ films (where x=15--37 at% and y=5--25 at%) with thickness of 200 nm are deposited by dc-magnetron sputtering. The MR ratio is sensitively dependent on the Tb concentration. The MR ratio is increased up to about 2.8% for a Tb concentration of about 22.4 at% then decreased for more Tb content. No significant effect of Co concentration on the MR ratio has been observed. The relation between MR ratio and film composition can be ascribed to the dependence of the domain wall width on the film concentration. The domain wall width decreases with an increase in Tb concentration and again increases for more Tb content showing its minimum value at about 22.4 at % of Tb concentration. It may be considered that the observed MR is contributed from the domain wall.     

Corrosion study in TbFeCoCr amorphous magneto-optical films

(Tb₂₀Fe₆₅Co₁₅)₉₄Cr ₆ film shows high corrosion resistance with good magnetooptical properties, H_c=4.9 kOe, &thetas;_k=0.3°, K_u=1.4×10⁶ erg/cm³ and T_c=230°C. Pit corrosion in 1N-NaCl aqueous solution and wet corrosion in 85°C and 85%RH atmosphere were studied for TbFeCo films with and without Cr addition. It is suggested that pit corrosion occurs by a chemical reaction between the anodic pit wall and the cathodic film surface, resulting in a piling up of corroded products inside the pits. On the other hand, wet corrosion in TbFeCo and TbFeCoCr films shows a bubble-chain-like morphology similar to conventional filiform corrosion observed in a coated film. This seems to take place by discontinuous movement of the anodic reaction area ahead of the bubbles     

聚焦光斑磁光极克尔磁滞回线的热效应分析

实验设计并组建了一套磁光极克尔磁滞回线测量装置,该装置可以通过改变照射到样品上的激光功率来改变薄膜样品上被聚焦光斑照射的测试点的温度。同时通过计算模拟了激光照射在TbFeCo磁光薄膜上的温度分布情况,得到了薄膜的矫顽力随照射激光功率的变化关系,由此可以确定薄膜的居里温度和补偿温度。为研究磁光薄膜样品在各种温度条件下,磁光性能的变化以及多层磁光薄膜的磁耦合效应提供了有效的手段。     

Estimation of thermal coefficients of magneto-optical media

Previously we described a method for estimating the thermal conductivity of magneto-optic recording media. The method relies on identifying the laser power that brings the maximum temperature of the TbFeCo layer to as high as the Curie temperature. We extensively use a similar method to estimate the heat capacity of a dielectric layer, a TbFeCo layer, and an aluminum alloy layer of magneto-optic recording media. Measurements are conducted on static disks with a beam of light focused on a TbFeCo layer. The method has the advantage of thermal diffusion depending on a multilayer structure and irradiation time.     

放电等离子烧结技术制备复合梯度靶材的研究

采用放电等离子烧结技术制备了TbFeCo／Ti和Bi2O3／Cu复合梯度靶材,利用扫描电子显微镜和能谱分析仪对材料的微观组织形貌及成分进行了分析。结果表明,合成的复合梯度靶材具有宏观组织不均匀性和微观组织连续性的特征,显微组织中不存在微裂纹。与单一靶材相比,TbFeCo／Ti复合梯度靶材解决了在制造和使用过程中容易碎裂的问题,Bi2O3／Cu复合梯度靶材解决了在溅射过程中的散热问题。     

Investigation of coercive squareness in TbFeCo films

TbFeCo is one of the most promising magnetooptical recording media because it shows a high uniaxial anisotropy and a fairly good Kerr effect, and its composition can be tailored to achieve a large room temperature coercivity. A basic study was carried out to determine the factors affecting the mechanisms of magnetization reversal and the regularity of domain growth at room temperature in TbFeCo films. A technique has been established to quantify the regularity of domain growth in terms of coercive squareness. It has been observed that intrinsic magnetization and uniaxial anisotropy are the two most significant parameters to affect coercive squareness. Deposition processes and conditions have a very slight influence on coercive squareness.<>