An AC magnetoelectric transport measurement system

Abstract

The invention discloses an AC magnetoelectric transport measurement system, comprising a signal generation and acquisition unit, a reaction unit and a main control unit; a sample to be tested is arranged inside the reaction unit, and the reaction unit provides the sample to be tested with adjustable temperature, illumination and Magnetic field; the signal generation and acquisition unit provides alternating current to the sample under test, and when the sample under test reacts, the signal generation and acquisition unit collects the signal component of the measured signal at both ends of the test sample that is in phase with the alternating current, and measures the voltage of the signal component; The control unit controls the frequency of the AC current of the signal generation acquisition unit, controls the temperature, illumination and the intensity of the magnetic field of the reaction unit, collects the data of the tested sample, and calculates the magnetoelectric transport capacity of the tested sample. The present invention can use alternating current to measure the magnetoelectric transport capability of the sample, and has high measurement precision and measurement efficiency.

Description

technical field [0001] The invention belongs to the technical field of semiconductor materials, and in particular relates to an AC magnetoelectric transport measurement system for measuring magnetoelectric transport of semiconductor materials. Background technique [0002] In the process of studying the physical properties of semiconductor materials and devices, magnetoelectric transport measurement is a very important and commonly used research method. By changing the external conditions such as temperature and magnetic field, it is possible to study the influence of external fields on the resistance, magnetoresistance, Hall coefficient, carrier concentration, mobility and other parameters of the sample. In the measurement of magnetoelectric transport, the sample is generally made into the shape of Vanderbilt or Hall bar. The Vanderbilt test does not have strict requirements on the symmetry of the sample, but it needs to take the average value of multiple measurements, and...

AI Technical Summary

Problems solved by technology

In this way, if more frequency points need to be tested, it will be time-consuming and very cumbersome

And in the follow-up process, it is found that the data at a certain temperature point is needed but has not been measured before, which requires repeating the experiment process again

[0005] The lock-in amplification technology used in the current AC magnetoelectric transport test system is obtained by adding the AC voltage signal generated by the internal oscillation of the lock-in amplifier to the two ends of the self-calibrating resistance, which causes the following problems: 1. . The calibration resistor is selected manually, which is easy to cause measurement errors; 2. In different environments, the value of the calibration resistor may change, resulting in the inability to obtain a constant AC current source; 3. Each measurement process requires When measuring different currents, it is necessary to replace the calibration resistor, which significantly reduces the efficiency of the measurement

[0006] In addition, light will have a significant impact on the magnetoelectric transport properties of semiconductors. However, most of the samples of similar magnetoelectric transport measurement systems are tested in a closed environment, and it is impossible to study the influence of light on the transport properties of semiconductor samples.

[0007] In order to overcome the shortcomings of the existing technology that direct current measurement is prone to produce many effects that reduce the measurement accuracy, the efficiency of alternating current measurement is low, and the influence of light on the measurement is not considered, an AC magnetoelectric transport measurement system is proposed.

Images