An ultra-low magnetic field thermal demagnetizer for high-precision paleomagnetism

Earth, Planets and Space

Jinhua Li¹  Greig A. Paterson²  Rixiang Zhu³  Shuhui Cai³  Shuangchi Liu³  Huafeng Qin³  Qingsong Liu⁴  Zhaoxia Jiang⁵  Xiang Zhao⁶ 

[1] Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China;Key Laboratory of Earth and Planetary Physics, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China;Department of Earth, Ocean and Ecological Sciences, University of Liverpool, L69 7ZE, Liverpool, UK;State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China;State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China;Department of Marine Science and Engineering, Southern University of Science and Technology, 518055, Shenzhen, China;State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China;Key Laboratory of Submarine Geosciences and Prospecting Techniques, Ministry of Education, and College of Marine Geosciences, Ocean University of China, 266100, Qingdao, People’s Republic of China;State Key Laboratory of Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Academy of Sciences, 100029, Beijing, China;Research School of Earth Sciences, Australian National University, ACT 2601, Canberra, Australia;

关键词: Paleomagnetism;    Thermal demagnetization;    Furnace;    AC magnetic field;    Residual magnetic field;    Heating wire structure;    Straight core solenoid;   

DOI  :  10.1186/s40623-020-01304-0

来源: Springer

【 摘 要 】

Thermal demagnetization furnaces are widely used paleomagnetic facilities for progressive removal of naturally acquired magnetic remanence or the imparting of well-controlled laboratory magnetization. An ideal thermal demagnetizer should maintain “zero” magnetic field in the sample chamber during thermal treatments. However, magnetic field noises, including the residual magnetic fields of the construction material and the induced fields caused by the alternating current (AC) in the heating element are always present, which can contaminate the paleomagnetic results at the elevated temperatures or especially for the magnetically weak samples. Here, we designed a new structure of heating wire named “straight core solenoid” to develop a new demagnetization furnace with ultra-low magnetic field noise. Simulation and practical measurements show that the heating current magnetic field can be greatly reduced by using the new technology. Thermal demagnetization experiments demonstrate that the new demagnetizer can yield low noise results even for weakly magnetic samples.

【 授权许可】

CC BY