Measuring system for enhancing magnetic circular polarization dichroism signal and promoting signal to noise ratio

Abstract

The invention discloses a measuring system for enhancing the dichroism signal of the magnetic circular polarization and improving the speech to the noise ratio. The system comprises an optical source, a monochromator, a first convex lens, a Wollaston prism, a photoelastic modulator, a photoelastic modulator controller, a second convex lens, a temperature changing magnetic body system, a detecting device and a lock-in amplifier. By using the invention, a measuring signal is enhanced and the speech to the noise ratio is improved; meanwhile, the relation between the dichroism signal of the magnetic circular polarization and an external magnetic field can be measured, and be corresponding to SQUID measured magnetic hysteresis loop; the relation between the dichroism signal of the magnetic circular polarization and the temperature also can be measured, and be corresponding to the temperature dependence of SQUID measured saturation magnetization or residual magnetization, and the curie temperature of a ferromagnetic of material can be confirmed; the dependency of the luminous energy of the dichroism signal of the magnetic circular polarization can be measured, to confirm the energy band structure of material.

Description

technical field [0001] The invention relates to the technical fields of semiconductor optical property testing and magnetic material testing, in particular to a measurement system for enhancing magnetic circular polarization dichroic signals and improving signal-to-noise ratio. Background technique [0002] Modern information technology uses the charge degree of freedom of electrons for information processing, and uses the spin degree of freedom of magnetic materials to store information. The emerging field of spintronics exploits these two degrees of freedom of electrons simultaneously to generate new functions, which may lead to future innovations in information technology. [0003] Diluted magnetic semiconductors have become the basis of applied materials for spintronics due to their simultaneous magnetic and semiconducting properties. The external magnetic field will cause the semiconductor energy band to split through the Zeeman effect, and the spin degeneracy of the s...

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Problems solved by technology

However, this instrument is very sensitive, and a small amount of impurities will affect the measurement results (Science, 312, pp1883-1884, 2006)

Moreover, this instrument can only measure the overall magnetization of the entire sample placed in the instrument, which is not conducive to obtaining the magnetization properties of a single-layer magnetic film

Therefore, although GaN:Mn, GaAs:Cr, and ZnO:Ni have been considered dilute magnetic semiconductors from SQUID measurements for a long time, no signal has been observed in magnetic circular dichroism measurements, so people wonder whether these materials Diluted magnetic semiconductors have always held different opinions

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