Room Temperature Scanning Micro-Hall Probe Microscope Imaging of Ferromagnetic Microstructures Under Large Pulsed Magnetic Fields Generated by an Integrated Mini-Coil

对磁畴在外磁场中的行为的基本理解对于信息技术的发展是重要的，例如超高密度磁记录介质、高矫顽力永磁体和用于制造新型“自旋电子”器件的多层铁磁结构。独特的磁成像系统，包括一个室温扫描霍尔探针显微镜，带有一个集成的微型线圈，能够产生高达3特斯拉的脉冲磁场（宽度为3.5ms）被开发用于在存在非常大的外部脉冲磁场的情况下对铁磁微畴进行直接和非侵入性的磁成像，而在测量期间不会对样品产生不利的振动干扰。该系统已成功地用于1.4MB写入软盘表面位模式擦除过程的磁成像和强脉冲外磁场作用下退磁锶铁氧体永磁体微畴结构的动力学研究，证明了微型线圈/RT-SHPM组合系统是一种有价值的直接、在存在大的外部偏置场的情况下，对磁记录介质和铁磁材料的表面处的局部杂散磁场进行定量和非侵入性观察。

A fundamental understanding of the behavior of magnetic domains in external magnetic fields is important for the development of information technology such as ultra-high density magnetic recording media, high coercivity permanent magnets and multilayered ferromagnetic structures used for fabricating novel 'spintronic' devices.In this research, a unique magnetic imaging system comprising of a room temperature scanning Hall probe microscope with an integrated mini-coil capable of generating pulsed magnetic fields up to 3 Tesla (width of 3.5ms) was developed for the direct and non-invasive magnetic imaging of ferromagnetic micro-domains in the presence of extremely large external pulsed magnetic fields without adverse vibrational disturbance of the sample during measurements. The system was successfully used for magnetic imaging of the erasure process of bit patterns on the surface of 1.4MB written floppy disks and the dynamics of micro-domain structures of demagnetized strontium ferrite permanent magnets under large external pulsed magnetic fields.The combined mini-coil/RT-SHPM system was demonstrated to be a valuable instrument for the direct, quantitative and non-invasive observation of localized stray magnetic fields at the surfaces of magnetic recording media and ferromagnetic materials in the presence large external bias fields.