Acquisition of high-temperature rock-magnetic instruments

该项目将通过收购两台新仪器来扩大岩石磁学研究所（IRM）的实验能力：第一台是Asylum Research MFP-3D磁力显微镜。该仪器在磁性材料样品表面以上的可控高度绘制磁场梯度的空间分布，分辨率为几十纳米，面积可达~100微米，从而可以观察材料的微磁结构（畴和畴壁）。除了室温成像外，MFP-3D还允许高达400°C的高温成像。这是通过MFP-3D XY扫描台上单独的高温环境级（poly加热器）完成的。加热和冷却可以在空气或受控环境中进行（例如He， Ar， CO等）。样品温度可保持在优于0.2°C的精度，精度可达0.5°C，温度超调小于0.2°C。所有的控制和测量功能是完全可编程的自定义加热-冷却成像实验。第二个是AGICO MFK1-FA卡帕布里奇和CS4炉。这个仪器既测量真实的？（同相）和？假想？（正交）具有复杂磁化率的元件，具有三个交流工作频率（976、3904和15616 Hz），应用交流场强范围从2a /m到最大700 a /m（取决于频率）。应用领域的高空间均匀性和仪器响应功能允许精确测量具有不同尺寸和形状的地质样品的磁各向异性，并且MFK1-FA中的集成标本旋转器可以快速自动获取与方向相关的数据。与MFK1-FA集成的CS4炉将能够在高温下测量频率和振幅相关的磁化率，这将是重要的新功能。这两种仪器的新高温能力将允许岩石磁学研究所的常驻和访问研究人员探索磁记忆的基本物理起源。在地质上具有重要意义的磁性物质中，如磁铁矿、钛磁铁矿、赤铁矿、血红铁矿和磁黄铁矿。这些矿物在微米到毫米大小的颗粒中的不均匀磁化为我们提供了古地磁记录。过去地磁场的强度和方向，使我们能够研究地球的演变？地球科学、生物科学、行星地质学和陨石学研究中的其他重要问题。通过观察矿物颗粒内的微磁结构及其随实验施加的磁场和控制温度的变化，我们可以研究自然磁记录的机制，了解它们在地质时期对热或化学套印的敏感性，并设计优化的实验室方法，从自然记录介质中恢复古磁场数据。

The project will expand experimental capabilities at the Institute for Rock Magnetism (IRM) through the acquisition of two new instruments:The first is a Asylum Research MFP-3D Magnetic Force Microscope. This instrument maps the spatial distribution of magnetic field gradients at a controlled height above the surface of a magnetic material sample, with a resolution of a few tens of nanometers, over areas up to ~100 micrometers, thereby allowing observation of the micromagnetic structure of the material (domains and domain walls). In addition to room-temperature imaging, the MFP-3D also allows high-temperature imaging up to 400°C. This is accomplished with a separate high temperature environmental stage (PolyHeater) that sits on the MFP-3D XY scanning stage. Heating and cooling can be done in air or controlled atmospheres (e.g., He, Ar, CO, etc). Sample temperature can be maintained to better than 0.2°C precision with accuracy to 0.5°C and temperature overshoots less than 0.2°C. All control and measurement functions are fully programmable for custom heating-cooling imaging experiments. The second is an AGICO MFK1-FA Kappabridge and CS4 Furnace. This instrument measures both ?real? (in-phase) and ?imaginary? (quadrature) components of complex susceptibility, with three AC operating frequencies (976, 3904 and 15616 Hz) and a range of applied AC field intensities from 2 A/m up to a maximum of 700 A/m (depending on frequency). High spatial uniformity of both applied fields and the instrument response function allow accurate measurement of the magnetic anisotropy of geological samples having various sizes and shapes, and an integrated specimen rotator in the MFK1-FA enables rapid automated acquisition of orientation-dependent data. The CS4 furnace, integrated with the MFK1-FA, will enable measurements of frequency- and amplitude-dependent susceptibility at elevated temperature, which will be important new capabilities. The new high-temperature capabilities of these two instruments will allow resident and visiting researchers at the Institute for Rock Magnetism to probe the fundamental physical origins of magnetic ?memory? in geologically significant magnetic materials such as magnetite, titanomagnetite, hematite, hemoilmenite, and pyrrhotite. The nonuniform magnetizations in micrometer-to-millimeter sized particles of these minerals provide us with the paleomagnetic ?recordings? of past geomagnetic field strength and orientation that allow us to study the evolution of the earth?s deep interior, the motion of tectonic plates, and other significant problems in the geosciences, biosciences, planetary geology, and meteoritic studies. Observation of the micromagnetic configurations within mineral grains, and their changes with experimentally applied fields and controlled temperatures, allows us to study the mechanisms of natural magnetic recording, to understand their sensitivity to thermal or chemical overprinting over geologic time, and to devise optimized laboratory methods for the recovery of paleomagnetic field data from natural recording media.