Exchange spring recording media for areal densities up to 10 Tbit/in2
Exchange spring recording media for areal densities up to 10 Tbit/in2
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DOI：
10.1016/j.jmmm.2004.11.525
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发表时间：
2005-04
影响因子：
2.7
通讯作者：
D. Suess;T. Schrefl;R. Dittrich;M. Kirschner;F. Dorfbauer;G. Hrkac;J. Fidler
中科院分区：
文献类型：
--
作者：
D. Suess;T. Schrefl;R. Dittrich;M. Kirschner;F. Dorfbauer;G. Hrkac;J. Fidler
为了实现10 Tbit/in 2的垂直记录面密度，需要直径约为3 nm的晶粒。然而，对于这样的晶粒尺寸，普通硬盘材料在磁性上太软而不能热稳定。诸如FePt的极硬磁性材料具有太大的矫顽场，并且不能用常规磁头场反转。与相同厚度的单相FePt层相比，所提出的FePt（2nm）/Fe 3 Pt（14 nm）/FePt（2nm）三层将矫顽场降低了8倍。与此同时，能量势垒仅降低了40%。由于开关场分布对硬层的易磁化轴与外场之间的夹角α不敏感，因此多层结构具有较高的信噪比。从α=0.1°到1°的变化，矫顽场的变化小于2.5%（传统垂直介质为10%）。因此，各向异性轴角度的小分布具有比常规垂直介质中更小的影响。
In order to achieve an areal density of 10Tbit/in2in perpendicular recording, grains with diameters of about 3nm are required. However, for such grain sizes, common hard disk materials are magnetically too soft to be thermally stable. Extremely hard magnetic materials such as FePt have a too large coercive field and cannot be reversed with conventional head fields. The proposed FePt (2nm)/Fe3Pt (14nm)/FePt (2nm) trilayer reduces the coercive field by a factor of 8 compared to a single-phase FePt layer of the same thickness. At the same time the energy barrier is only decreased by 40%. A high signal to noise ratio can be expected for the multilayer structure since the switching field distribution is insensitive on the angle α between the easy axis of the hard layers and the external field. A change from α=0.1° to 1° changes the coercive field by less than 2.5% (10% for conventional perpendicular media). Thus, small distribution of the anisotropy axes angles have less effect than in conventional perpendicular media.