Studies on Bloch Line Memory for Practical Use

为了将诺贝尔固态磁存储器（Bloch线存储器）实际应用，在LPE石榴石薄膜上处理的10mbit /cm^2 Bloch线存储器（标称条纹宽度为5um）的测试芯片中确认了以下存储功能。1. 采用热磷酸湿法刻蚀形成平行槽形，构建了1 mm^2的VBL存储区。2. 制作了计算机控制的芯片测试仪，并通过芯片测试仪对多个条带域的同时读写操作进行了验证。3. 数值研究了周期性图案化铬膜引起的应力诱导各向异性对钻头稳定的影响。根据数值结果得出的设计准则，在测试芯片上实现了vbl的位传播。4. 提出了一种具有较大误差容差的主线气泡传播路径结构。在测试芯片上处理了带有气泡传播路径的读写门。在芯片上确认了顺序门操作，即从vbl到气泡的位信息转换，气泡传播，气泡拉伸。在LPE石榴石薄膜上处理具有合理操作余量的读写门，用于40mbit /cm^2 Bloch线存储器（标称条纹宽度为2um），作为增加位密度的下一步。数值研究了壁合并过程中细观微磁结构的时空变化规律。发现读取操作误差是由动态壁结构变化（水平布洛赫线成核）引起的，明确了抑制读取操作误差的操作条件。推导出了有效退磁压力的精确数学公式。对于特性因子较小的材料（q=2.8），用于100mbit /cm^2以上的布洛赫线存储器，用公式模拟的结果与理论吻合较好。少

In order to put a nobel solid state magnetic memory (Bloch line memory) to practical use, the following memory functions were confirmed in a test chip processed on a LPE garnet film for 10 Mbit/cm^2 Bloch line memory (nominal stripe width is 5 um). 1. VBL storage area of 1 mm^2 was constructed by parallel grooved patterns formed by the wet etching method using heated phosphoric acid. 2. A computer controlled chip tester was fabricated, and the simultaneous read and write operations for multiple stripe domains was confirmed by the chip tester. 3. Bit stabilization effect due to the stress induced anisotropy caused by periodically patterned Cr film was studied numerically. Bit propagation of VBLs was realized in a test chip, which was fabricated according to the design criteria obtained from the numerical results. 4. A new architecture of major line bubble propagation path having large misalignment tolerance was processed. A read-write gate with the bubble propagation path was processed … More on a test chip. Sequential gate operations, that is, conversion of bit informations from VBLs to bubbles, bubble propagation, bubble stretching, were confirmed on the chip.A read-write gate having reasonable operation margin was processed on a LPE garnet film for 40 Mbit/cm^2 Bloch line memory (nominal stripe width is 2 um) as a next step to increase the bit density. The temporal and spatial variations of the detailed micromagnetic structures during the wall merging process was studied numerically. It was found that the read operation error was caused by the dynamic wall structure change (nucleation of the horizontal Bloch line), and the operation condition to suppress it was clarified. Furthermore, An accurate mathematical formula for the effective wall-demagnetizing pressure was derived. The simulated result using the formula agreed well with the theory in the case of material with small characteristics factor (q=2.8), which would be used for Bloch line memory of more than 100 Mbit/cm^2. Less