Bit patterned structure fabricated by Kr+ ion irradiation onto MnBiCu films
Bit patterned structure fabricated by Kr+ ion irradiation onto MnBiCu films
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MnBiCu 薄膜上 Kr 离子辐照制备位图结构
DOI：
10.1109/tmag.2012.2198052
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Q. Xu
中科院分区：
文献类型：
--
作者：
池田 翔;伊藤浩之;石原昇;益一哉;D. Oshima;B.Dai;T. Kato;Q. Xu
在350°C的温度下对溅射的MnCu/Bi多层膜进行热处理，制备了具有垂直各向异性的Mn54Bi24Cu21(15 Nm)薄膜，该薄膜表面平坦，fRa=1.1 nm，在离子辐照前观察到均匀的迷宫结构。在Kr+离子剂量为5×10~(13)ion/cm~2时，薄膜的磁化强度和矫顽力消失。利用电子束光刻制作的抗蚀剂掩模，用30kVKr+离子辐照制备了基于MnBiCu(15 Nm)薄膜的位图案化介质。离子辐照BPM膜的表面与退火态BPM膜的表面基本一致。通过施加磁场后的磁力显微镜观察研究了位图案化介质的磁化过程。尺寸从500×500 nm到300×300 nm的图案化的MnBiCu位具有多域态，其磁化反转经历了反转磁畴的成核和壁传播。通过减小图案化的MnBiCu的位尺寸，增加了位的平均开关场Hsf。这意味着图案化比特和比特边缘损伤之间的交换耦合可以忽略不计，并且显示了高密度离子辐照平面比特图案化介质的可能性。
Mn54Bi24Cu21(15 nm) films with a perpendicular anisotropy were prepared by annealing the sputtered MnCu/Bi multilayer at a temperature of 350 °C. The MnBiCu film had a rather flat surface ofRa= 1.1 nm, and uniform maze domain was observed before the ion irradiation. The magnetization and coercivity of the MnBiCu film were confirmed to disappear after a low Kr+ion dose of 5 ×1013ions/cm2. Bit patterned media (BPM) using the MnBiCu (15 nm) films were fabricated by 30 kV Kr+ion irradiation through electron beam lithography-made resist masks. The surface of the ion-irradiation BPM was almost identical to that of the as-annealed film. The magnetization processes of the bit patterned media were investigated by magnetic force microscope observations after application of the magnetic field. The patterned MnBiCu bits with a size ranging from 500 × 500 nm to 300 × 300 nm have a multidomain state and their magnetization reversals undergo nucleations of the reversed domain and wall propagation. By decreasing the bit size of the patterned MnBiCu, the average switching fieldHsfof the bits was increased. This means that the exchange coupling between the patterned bits and the bit edge damage were negligibly small, and shows the possibility of high density ion irradiated planar bit patterned media.