A Scanning Hall Probe Microscope for High Resolution milliKelvin Magnetic Imaging

用于高分辨率毫开尔文磁成像的扫描霍尔探针显微镜

• 批准号: EP/D034264/1
• 负责人: Simon Bending
• 金额: $ 34.16万
• 依托单位: University of Bath
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2006
• 资助国家: 英国
• 起止时间: 2006 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FD034264%2F1
• 关键词: Scanning; Hall; Probe; Microscope; Resolution

Some of the most exciting contemporary problems in condensed matter physics are in the area of nanoscale quantum mechanics and relate to the properties of superconducting and ferromagnetic materials at ultra-low temperatures, e.g. in the study of macroscopic quantum tunnelling and novel forms of quantum order. A key aspect of this work is the ability to perform high spatial resolution magnetic imaging down to ultra-low temperatures and/or at high magnetic fields. Due to the major technical challenges posed in these regimes, no magnetic imaging system currently exists which is capable of nanoscale imaging. Over the last decade we have successfully developed a number of scanning Hall probe microscopes (SHPMs) in Bath which span the temperature range 4.2-300K. These Hall probe systems represent a very flexible approach to magnetic imaging since Hall sensors can readily be fabricated with ~100nm spatial resolution and excellent minimum detectable fields and, using high probe current densities, can be operated in magnetic fields of several Teslas. All existing SHPM systems use 4He exchange gas cooling and, hence, can only be operated above 4.2K. In order to address a range of exciting contemporary problems in magnetic materials at much lower temperatures we propose to design and construct a new SHPM head which can be directly attached to the 300mK cold pot of a commercial 3He cryostat insert. This instrument will be capable of operation in magnetic fields up to 10T with a spatial resolution >100nm and minimum detectable field ~10mG/Hz^0.5. Its unique properties will be exploited to open up a new front in the field of nanoscale quantum phenomena. Within the project we will search for novel vortex structures and spontaneously generated flux in the unconventional superconductor Sr2RuO4, and will attempt to establish the mechanism for macroscopic quantum tunnelling of the magnetisation in the molecular magnet Mn12-acetate. In addition we will search for new geometry-driven vortex structures in mesoscopic Al disks.

当代凝聚态物理中一些最令人兴奋的问题是在纳米尺度的量子力学领域，涉及超导和铁磁材料在超低温下的性质，例如在宏观量子隧道和新形式的量子有序的研究中。这项工作的一个关键方面是能够在超低温和/或高磁场下执行高空间分辨率的磁成像。由于这些体制带来的重大技术挑战，目前还不存在能够进行纳米级成像的磁成像系统。在过去的十年里，我们已经成功地开发出了一些在Bath中的扫描霍尔探针显微镜(SHPM)，其温度范围为4.2-300K。这些霍尔探头系统代表了一种非常灵活的磁成像方法，因为霍尔传感器可以很容易地制造成具有~100 nm空间分辨率和出色的最小可探测场，并且使用高探头电流密度，可以在几个特斯拉的磁场中运行。所有现有的SHPM系统都使用4He交换气体冷却，因此只能在4.2K以上工作。为了解决当代磁性材料在更低温度下的一系列令人兴奋的问题，我们建议设计和构造一种新的SHPM磁头，它可以直接连接到商用3He低温恒温器的300mK冷锅上。该仪器将能够在高达10T的磁场中工作，空间分辨率为&gt；100 nm，最小可探测磁场为~10 mg/hz^0.5。它的独特性质将被用来开辟纳米量子现象领域的新前沿。在该项目中，我们将在非传统超导体Sr2RuO4中寻找新的涡旋结构和自发产生的磁通，并试图建立分子磁体Mn12-醋酸酯中磁化的宏观量子隧道机制。此外，我们还将在介观铝盘中寻找新的几何驱动的涡旋结构。

项目成果

Scanning Hall Probe Imaging of Nanoscale Magnetic Structures

纳米级磁性结构的扫描霍尔探针成像

• DOI: 10.1166/sl.2009.1099
• 发表时间: 2009
• 期刊: Sensor Letters
• 作者: Bending S

Vortex 'puddles' and magic vortex numbers in mesoscopic superconducting disks

介观超导盘中的涡旋“水坑”和魔幻涡旋数

• 发表时间: 2009
• 期刊: J.Phys.Conf.Ser. 150
• 作者: M.R.Connolly;et al.
• 通讯作者: et al.