An Ultra-low Magnetic Field Thermal Demagnetizer for High-precision Paleomagnetism

Abstract 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 often greatly contaminate the paleoamgnetic results at the elevated temperatures or for the magnetically weak samples. Here, we designed a new structure of heating wire named named straight core solenoid to develop a new demagnetization furnace with ultra-low magnetic field noise. Simulation and practical measurement 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.

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

Earth Planets and Space ◽

10.1186/s40623-020-01304-0 ◽

2020 ◽

Vol 72 (1) ◽

Author(s):

Huafeng Qin ◽

Xiang Zhao ◽

Shuangchi Liu ◽

Greig A. Paterson ◽

Zhaoxia Jiang ◽

...

Keyword(s):

Magnetic Field ◽

Elevated Temperatures ◽

Construction Material ◽

New Technology ◽

Low Noise ◽

Zero Magnetic Field ◽

Thermal Demagnetization ◽

Sample Chamber ◽

Weakly Magnetic ◽

Low Magnetic Field

Abstract 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.

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

10.21203/rs.3.rs-50114/v1 ◽

2020 ◽

Author(s):

Huafeng Qin ◽

Xiang Zhao ◽

Shuangchi Liu ◽

Greig A. Paterson ◽

Zhaoxia Jiang ◽

...

Keyword(s):

Magnetic Field ◽

Elevated Temperatures ◽

Construction Material ◽

New Technology ◽

Low Noise ◽

Zero Magnetic Field ◽

Thermal Demagnetization ◽

Sample Chamber ◽

Weakly Magnetic ◽

Low Magnetic Field

Abstract 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 often greatly contaminate the paleoamgnetic results at the elevated temperatures or for the magnetically weak samples. Here, we designed a new structure of heating wire named named straight core solenoid to develop a new demagnetization furnace with ultra-low magnetic field noise. Simulation and practical measurement 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.

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

10.21203/rs.3.rs-54689/v3 ◽

2020 ◽

Author(s):

Huafeng Qin ◽

Xiang Zhao ◽

Shuangchi Liu ◽

Greig Paterson ◽

Zhaoxia Jiang ◽

...

Keyword(s):

Magnetic Field ◽

Elevated Temperatures ◽

Construction Material ◽

New Technology ◽

Low Noise ◽

Zero Magnetic Field ◽

Thermal Demagnetization ◽

Sample Chamber ◽

Weakly Magnetic ◽

Low Magnetic Field

Abstract 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 paleoamgnetic 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.

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

10.21203/rs.3.rs-54689/v2 ◽

2020 ◽

Author(s):

Huafeng Qin ◽

Xiang Zhao ◽

Shuangchi Liu ◽

Greig Paterson ◽

Zhaoxia Jiang ◽

...

Keyword(s):

Magnetic Field ◽

Elevated Temperatures ◽

Construction Material ◽

New Technology ◽

Low Noise ◽

Zero Magnetic Field ◽

Thermal Demagnetization ◽

Sample Chamber ◽

Weakly Magnetic ◽

Low Magnetic Field

Abstract 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 paleoamgnetic 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.

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TRANSPORT PROPERTIES OF 2D ELECTRON GAS IN AN n-InGaAs/GaAs DQW IN A VICINITY OF LOW MAGNETIC-FIELD-INDUCED HALL INSULATOR–QUANTUM HALL LIQUID TRANSITION

International Journal of Nanoscience ◽

10.1142/s0219581x07004523 ◽

2007 ◽

Vol 06 (03n04) ◽

pp. 173-177

Author(s):

YU. G. ARAPOV ◽

S. V. GUDINA ◽

G. I. HARUS ◽

V. N. NEVEROV ◽

N. G. SHELUSHININA ◽

...

Keyword(s):

Magnetic Field ◽

Electron Gas ◽

Quantum Hall ◽

Zero Magnetic Field ◽

Double Quantum ◽

Ballistic Regime ◽

2D Electron Gas ◽

Double Quantum Well ◽

Liquid Transition ◽

Low Magnetic Field

The resistivity (ρ) of low mobility dilute 2D electron gas in an n- InGaAs / GaAs double quantum well (DQW) exhibits the monotonic "insulating-like" temperature dependence (dρ/dT < 0) at T = 1.8–70 K in zero magnetic field. This temperature interval corresponds to a ballistic regime (kBTτ/ħ > 0.1–3.5) for our samples, and the electron density is on an "insulating" side of the so-called B = 0 2D metal–insulator transition. We show that the observed features of localization and Landau quantization in a vicinity of the low magnetic-field-induced insulator–quantum Hall liquid transition is due to the σxy(T) anomalous T-dependence.

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A new furnace for improving thermal demagnetization in paleomagnetism

10.5194/egusphere-egu2020-6879 ◽

2020 ◽

Author(s):

Huafeng Qin ◽

Xiang Zhao ◽

Shuangchi Liu ◽

Greig Paterson ◽

Zhaoxia Jiang ◽

...

Keyword(s):

Magnetic Field ◽

Curie Temperature ◽

High Performance ◽

Thermal Treatments ◽

Thermal Demagnetization ◽

Heating Wire ◽

Low Magnetic Field ◽

Detrimental Impact ◽

The Magnetic Field ◽

The Ideal

<p>Thermal demagnetization furnaces are routine facilities for paleomagnetic studies. The ideal thermal demagnetizer should maintain &#8220;zero&#8221; magnetic field during thermal treatments. However, magnetic field noises, including residual magnetic fields of material and induced fields caused by the heating current in the furnace are always present. The key to making high-performance demagnetization furnace is to reduce the magnetic field noises. By combining efficient demagnetization of shielding and a new structure of heating wire, we have developed a new demagnetization furnace with low magnetic field noises. Repeated progressive thermal demagnetization experiments using specimens that were previously completely thermal demagnetized above their Curie temperature were carry out to explore the effects of field within various types of furnace during demagnetization. These experiment confirm that magnetic field noises in the furnace can have an observable and detrimental impact on demagnetization behavior. Comparison between commercial furnaces and our new design show a notable reduction in the impacts of on thermal demagnetization behavior. The new heating element design and procedure for reducing magnetic&#160;field&#160;noises represent a significant improvement in the design of thermal demagnetizers and allows for extremely weak specimens to be successfully measured.</p>

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Chip-Scale Ultra-Low Field Atomic Magnetometer Based on Coherent Population Trapping

Sensors ◽

10.3390/s21041517 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1517

Author(s):

Hyun-Gue Hong ◽

Sang Eon Park ◽

Sang-Bum Lee ◽

Myoung-Sun Heo ◽

Jongcheol Park ◽

...

Keyword(s):

Magnetic Field ◽

Ground State ◽

Coherent Population Trapping ◽

Zero Magnetic Field ◽

Zero Field ◽

Resonance Signal ◽

Low Field ◽

Low Magnetic Field ◽

Population Trapping ◽

Wide Operating

We report a chip-scale atomic magnetometer based on coherent population trapping, which can operate near zero magnetic field. By exploiting the asymmetric population among magnetic sublevels in the hyperfine ground state of cesium, we observe that the resonance signal acquires sensitivity to magnetic field in spite of degeneracy. A dispersive signal for magnetic field discrimination is obtained near-zero-field as well as for finite fields (tens of micro-tesla) in a chip-scale device of 0.94 cm3 volume. This shows that it can be readily used in low magnetic field environments, which have been inaccessible so far in miniaturized atomic magnetometers based on coherent population trapping. The measured noise floor of 300 pT/Hz1/2 at the zero-field condition is comparable to that of the conventional finite-field measurement obtained under the same conditions. This work suggests a way to implement integrated atomic magnetometers with a wide operating range.

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