Studies Of Characterization And Measuring Technologies Of Hybrid Recording Media

This dissertation is on the researches that magnetic characterization and techniques of hybrid recording media are proposed closely relating to the problems of thermal stability, effect of exchange coupling and media noise, and that the two integrated systems of characterization setups and experiment methods are presented respectively according to large and small scale. These researches will play a role not only in magnetic characterization and measuring static reading/writing property of hybrid recording media, but also in advanced characterization techniques and synthetic characterization platform. First, the characterization parameters are divided into many classifications according to their features and a scheme of characterization space on hybrid recording media is described; and then, the characterization sets are evolved and expanded along with a route of magnetic hysteresis, magnetic torque cueve and remanent magnetization curves, moreover, the relating problems on charcterization are discussed, such as meaning of characteristic parameters and measurement techniques and so on. According to Preisach model a model-based characterization method of magnetic hysteresis andΔM curve is presented.From view of matter scale, there are two kinds of proposed different characterization hierarchies on hybrid recording: 1) synthetical characterization techniques of large scale basic static magnetic parameters; and 2) that of local optical and magnetic properties. In two hierarchies, there are two corresponding characterization integrated systems or platforms:1) railway-and bus-based system integration techniques on vibrating sample magnetometer, torque magnetometer and magnetoresistance testing apparatus; and 2) a synthetical characterization platform of optical and magnetic properties on which magnetic-optical kerr effect measurement system and polarized-light-microscopy-based R/W performance test and magnetic domain observation apparatus are integrated. Firstly, theoretically, these principles of VSM, torque magnetometer, magnetoresistance measurement, polar kerr effect measurement and polarized light microscopy are studied, and on the base of theoretical research, the space distribution of sensitivity function on VSM, the system model of magnetic anistropy measurement, the detecting theory of polar Kerr effect and noise model of photoelectric element are discussed detailedly. Secondly, frame model of hardware system integration about larger scale basic static magnetic characterization, software functional model and information processing model based on railway and bus are designed; for the synthetical characterization platform, a three-hierarchy model is proposed, in which data are its core including management, transmission, storage, processing and visualization of data. Finally, a variable-structure measurement method and its implement is studied.In the aspect of application, CoCrPt and TbFeCo thin films are considered as candidates of hybrid recording media, and so the Cr layer dependence and annealing dependence of magnetic property for CoCrPt thin films are investigated. For TbFeCo system thin films, the temperature dependence and the Tb composition dependence of perpendicular magnetization are investigated.