Computer model calculations and experimental comparison are presented for thermomagnetic writing in TbFe media. Two models are discussed which are appropriate for two observed types of writing behavior. A lsquo;lsquo;bubblersquo;rsquo; type writing model is found to give good experimental agreement when wall motion processes dominate and the laserhyphen;written marks exhibit singlehyphen;domain behavior. This model accurately accounts for the writing behavior of Tb0.23Fe0.77. The gradient of the domainhyphen;wall energy is found to be an important factor in the writing process and can cause nucleation to be delayed until some cooling has occurred. This results in written domain sizes which are a strong function of the applied bias field. For compositions which exhibit multiple domain writing behavior, a lsquo;lsquo;nucleation fieldrsquo;rsquo; model is found to be appropriate. This model predicts the observed weak dependence of mark size on applied bias field. In addition, the nucleation field model is used to calculate the bias fields which correspond to the onset of writing (onset field) and singlehyphen;domain mark formation (saturation field).
展开▼
