This thesis has been devoted to deposition process, structures, magnetic properties and time-dependence effect of CoCrTa magnetic thin films for recording media. The experimental study began from Chapter 5 by investigating properties of single layer CoCrTa thin films, produced under different sputtering conditions. Next, in Chapter 6, structure of Cr single layer has been studied separately, in order to find a key to control the crystallography of this layer. After that, the CoCrTa layer was deposited onto the Cr underlayer, to form a configuration of typical longitudinal recording media. The dependence of various properties of CoCrTa/Cr media samples on thickness of each constituent layer has been investigated. In the second half of the thesis, which was presented in Chapter 7, we concentrated on the timedependence effect in CoCrTa media samples, as both longitudinal (in-plane) and perpendicular media. The field dependence of viscosity, which belongs to the time-dependence effect, was the main subject of this study. In addition to CoCrTa media, we also studied perpendicular alumite media because this type of media is considered a good model to study various magnetic behaviors of recording media.