Controlling domain configuration of the sensing layer for magnetic tunneling junctions by using exchange bias
Controlling domain configuration of the sensing layer for magnetic tunneling junctions by using exchange bias
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DOI：
10.1063/1.5130486
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发表时间：
2020-02
期刊：
影响因子：
1.6
通讯作者：
S. Ranjbar;M. Al-Mahdawi;M. Oogane;Y. Ando
中科院分区：
文献类型：
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作者：
S. Ranjbar;M. Al-Mahdawi;M. Oogane;Y. Ando
控制传感层中的磁畴形成和波动对于磁隧道结传感器中的低噪声进展是重要的。研究了微图案化坡莫合金（Py：Ni_（80）Fe_（20））敏感层中交换偏压对磁畴结构的影响。我们沉积了单一的Py膜，和Pt 48 Mn 52/Py膜，其中后者表现出交换偏置。通过控制Py的厚度，Pt 48 Mn 52（15 nm）/Py（t=235 nm）表现出较小的矫顽磁力和7 Oe的交换偏置。微加工成直径80 µm的圆形柱后，我们通过磁光克尔效应（MOKE）显微镜测量了磁畴结构。MOKE图像显示，单个Py柱具有简单的闭合域，其中中心处的域壁随着施加的场而移动。交换偏置的Py柱表现出更复杂的结构，但由于交换偏置克服了静磁能，在中心区域具有固定的畴。样品中心磁化强度的均匀旋转有利于降低畴跳磁噪声。
The control of magnetic domain formation and fluctuations in the sensing layer is important to progress for low noise in magnetic tunnel junction sensors. We studied the effect of exchange bias on the domain structure in micro-patterned Permalloy (Py: Ni80Fe20) sensing layer. We deposited single Py films, and Pt48Mn52/Py films, where the latter showed exchange bias. By controlling the thickness of Py, Pt48Mn52 (15nm)/Py (t=235 nm) showed a small coercivity and exchange bias of 7 Oe. After micro-fabrication into circular pillars 80 µm in diameter, we measured the domain structure by Magneto Optical Kerr Effect (MOKE) microscopy. MOKE images showed that single Py pillars have a simple closure domain, where the domain wall at the center moved with the applied field. The exchange-biased Py pillars exhibited a more complicated structure, but with fixed domains at the center region due to the exchange bias overcoming the magnetostatic energy. The uniform rotation of magnetization at the center of the sample is promising for decreasing the domain hopping magnetic noise.