Wautischer Gregor, Abert Claas, Bruckner Florian, Slanovc Florian, Suess Dieter
Faculty of Physics, University of Vienna, Vienna, Austria.
Research Platform MMM Mathematics-Magnetism-Materials, University of Vienna, Vienna, Austria.
Sci Rep. 2022 Aug 17;12(1):13986. doi: 10.1038/s41598-022-18112-z.
In this work, the possibility to reduce transition curvature in heat-assisted magnetic recording, using a conventional write head design, by shaping the recording field to counteract the circular profile of the heat pulse is investigated. Topology optimization of the head tip is performed in order to create the desired cross-track field profile for increasing distances from the write head tip. For the topology optimization, the adjoint method is utilized to calculate the necessary gradients and a binary optimization scheme is proposed. The optimizations are performed considering linearized material parameters reducing the computational complexity and the results are compared to optimizations incorporating the full non-linear material behavior. The optimized field profiles are evaluated for their influence on the read-back process. To do so, switching probability phase diagrams are calculated and the curvature parameter, the signal to noise ratio and the channel bit density are extracted. The presented results show that while transition curvature can be reduced by shaping the cross-track profile of the write field, this alone does not consequently lead to an improvement of the read back process. Therefore, completely new head designs, considering additional parameters have to be investigated.
在这项工作中，研究了通过塑造记录场以抵消热脉冲的圆形轮廓，利用传统写头设计来降低热辅助磁记录中转换曲率的可能性。对磁头尖端进行拓扑优化，以创建所需的跨轨场轮廓，用于增加与写头尖端的距离。对于拓扑优化，利用伴随方法计算所需梯度，并提出了一种二元优化方案。考虑线性化材料参数进行优化以降低计算复杂度，并将结果与包含完全非线性材料行为的优化结果进行比较。评估优化后的场轮廓对回读过程的影响。为此，计算开关概率相图，并提取曲率参数、信噪比和通道比特密度。给出的结果表明，虽然可以通过塑造写场的跨轨轮廓来降低转换曲率，但仅此一点并不能必然导致回读过程的改善。因此，必须研究考虑其他参数的全新磁头设计。
