Method for rapidly acquiring size and distribution of ultra-fast demagnetization of material

Abstract

The invention relates to a material analyzing and testing method, and particularly relates to a method for rapidly acquiring size and distribution of ultra-fast demagnetization of a material. The method specifically comprises the following steps: measuring and researching crystallography parameters of the material by using an X-ray diffracmeter, wherein the crystallography parameters include the spatial symmetric group to which the material belongs, a lattice constant and a fractional coordinate to which each atom corresponds; acquiring the ground state property of the material by applying a density functional theory in combination with the crystallography parameters of the material, wherein the ground state property mainly comprises a magnetic moment, a Fermi surface and an energy band structure of the material; determining spin density matrixes and electric dipole transition matrixes on a k point inside a reduced brillouin zone of the researched material; calculating a spin expected value difference matrix, a dipole transition matrix, and an energy window selecting matrix; researching the size of the demagnetization of the material; and acquiring the distribution situation of a femtosecond magnetism in a whole momentum space through symmetry operation. The method has the characteristics of being small in desired resource, low in cost, and simple and feasible.

Description

technical field [0001] The invention relates to a material analysis and test method, especially a method for rapidly obtaining the size and distribution of ultrafast demagnetization of materials. Background technique [0002] In femtoseconds (10 -15 Second) laser pulses, the magnetic properties of the material will drop sharply in a very short time—ultrafast demagnetization. The study of the demagnetization mechanism and the behavior that can effectively manipulate the electron spin are called femtosecond magnetism. . Based on this research, people are expected to make a major breakthrough in magnetic storage technology. In magnetic memory, data storage speed depends on the speed of inversion of electron spin. With the assistance of femtosecond laser pulses, magnetic materials can achieve ultrafast demagnetization, which can reverse the spin within femtoseconds, so the data storage speed can be greatly improved. Compared with the current commercial magnetic storage speed...

AI Technical Summary

Problems solved by technology

However, these experimental methods can only measure the demagnetization information in real space, while the properties of more momentum spaces cannot be touched, which undoubtedly hinders the development of femtosecond magnetism

Although angle-resolved photoelectron (AR-PE) enables the measurement of momentum space, the technique is limited to the measurement of the dynamical properties of charges, lattices or electrons

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