A nonlocal resistive NMR measurement method

A nuclear magnetic resonance and measurement method technology, applied in the field of spintronics, can solve problems such as hindering detection and characterization, and achieve the effects of avoiding the generation of Joule heating, reducing Hall bias, and slightly changing sensitivity

Active Publication Date: 2021-08-31
JILIN UNIV
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Problems solved by technology

At this time, the measured substate is actually in a non-equilibrium state, which seriously hinders the detection and characterization of its intrinsic properties.
However, the effect of Hall bias on the quantum state has been seriously ignored in previous transport measurements and resistive NMR measurements.

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  • A nonlocal resistive NMR measurement method
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  • A nonlocal resistive NMR measurement method

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Embodiment Construction

[0021] The technical solution of the present invention will be specifically described below in conjunction with the accompanying drawings.

[0022] Schematic diagram of InSb / AlInSb two-dimensional electron gas Hall strip sample figure 1 As shown, the Hall measuring area 1 has a length of l-100 μm and a width of w-30 μm. The sample Landes g factor g ~ -50, effective mass m ~ 0.015m e (m e : electron effective mass), the electron gas density is 2.8×10 15 m -2 , Electron mobility is 19m 2 / Vs, these parameters ensure that all electrons only occupy the first subband of the two-dimensional electron gas energy band and form a quantum Hall ferromagnetic state under the condition of lower than the maximum working magnetic field (15T) in the laboratory. The quantum state is formed when the angle between the normal line of the sample and the direction of the static magnetic field of the additional magnet of the thermostat is ~64°, and the magnetic field is ~13T. The longitudinal re...

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Abstract

A non-local resistive NMR measurement method of the present invention belongs to the technical field of spintronics, and the main steps include: placing a two-dimensional electron gas Hall strip sample for non-local measurement on a sample rotating table In the cryostat, a quantum Hall ferromagnetic state with a magnetic domain structure is formed; non-local resistance measurement is performed on the quantum Hall ferromagnetic state, and the quantum Hall ferromagnetic state is obtained according to the relationship between the resistance peak and the inclination angle of the quantum Hall ferromagnetic state. According to the obtained NMR spectrum, the nuclear spin relaxation time T of the quantum Hall ferromagnetic state is measured. 1 and nuclear spin decoherence time T 2 Measurement. Through the introduction of the non-local measurement configuration, the present invention realizes the dynamic nuclear polarization under small current, thereby ensuring that the measured sub-state is always in an equilibrium state, and the non-local resistance of the measured sub-state is 2 orders of magnitude smaller than the normal measurement resistance , which improves the precision of resistive NMR measurement by an order of magnitude.

Description

technical field [0001] The invention belongs to the technical field of spintronics, and relates to a method with ultra-high sensitivity and minimally invasive detection of quantum state intrinsic characteristics and novel topological states. Background technique [0002] NMR technology with ultra-high detection sensitivity, accuracy and resolution has been widely used in many scientific research fields. Usually, high signal-to-noise ratio measurements require that the number of sample nuclei measured by this technique is not less than 10 15 . Obviously, this requirement is difficult to be met in low-dimensional materials or devices (for example, the number of atomic nuclei in a two-dimensional electron gas system confined by a semiconductor single quantum well is less than 10 8 ). To this end, the discoverer of the quantum Hall effect, the von Klitzing research team at the Max Planck Institute in Germany, used the dynamic nuclear polarization method induced by electron sp...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N24/08
CPCG01N24/085
Inventor 刘洪武杨凯锋
Owner JILIN UNIV
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