Magnetic nano temperature measurement method using triangle wave excitation magnetic field

摘要

Provided is a magnetic nano temperature measurement method under a triangle wave excitation magnetic field relating to a technical field of nano measurement. The method further comprises steps of: (1) positioning a magnetic nano sample at a measured object; (2) applying a triangle wave excitation magnetic field on area of the magnetic nano sample; (3) detecting a triangle wave excitation magnetic field-time curve and a magnetization-time curve of the magnetic nano sample; (4) obtaining a magnetizing curve of the magnetic nano sample, namely excitation magnetic field-magnetization curve, by the triangle wave excitation magnetic field curve and the magnetization curve, and sampling the magnetizing curve to obtain magnetization Mi of the magnetic nano sample under excitation magnetic field Hi; and (5) determining temperature of the measured object by curve fitting with excitation magnetic field Hi as input, magnetization Mi as output, and a relationship between the excitation magnetic field and the magnetization as objective function. The invention obtains a magnetizing curve rapidly using a triangle wave excitation magnetic field, and realizes real-time and precise temperature measurement based on magnetic nanoparticles by inversion algorithms according to the magnetizing curve based on a temperature measurement model of magnetic nanoparticles under a DC magnetic field.

主权项

1. A magnetic nano temperature measurement method under a triangle wave excitation magnetic field, comprising steps of:
(1) positioning a magnetic nano sample at a measured object; (2) applying said triangle wave excitation magnetic field on area of said magnetic nano sample; (3) detecting a triangle wave excitation magnetic field-time curve and a magnetization-time curve of said magnetic nano sample; (4) sampling said triangle wave excitation magnetic field-time curve and said magnetization-time curve thereby obtaining magnetization Mi of said magnetic nano sample under excitation magnetic field Hi, where i=1, . . . , n and n is the total number of sampling points; and (5) determining temperature T of said measured object by curve fitting with excitation magnetic field Hi as input, magnetization Mi as output, and a relationship between the excitation magnetic field and the magnetizationMi=NMs⁡[coth⁡(Ms⁢HikT)-kTMs⁢Hi]  as objective function, where N is concentration of said magnetic nano sample, Ms is effective magnetic moment of a magnetic nanoparticle, and k is Boltzmann's constant.