The invention relates to a preparation method of a transmission
electron microscope observation sample of a magnetic liquid in a
magnetic field. According to the invention, a certain amount of the magnetic liquid is dispersed in a
solvent, such that a mixed liquid is formed; the mixed liquid is subjected to
ultrasonic oscillation for approximately 15min, such that the magnetic liquid is uniformly dispersed and is suspended in the
solvent, and a transparent dispersion liquid is formed; the dispersion liquid is placed in a
transverse magnetic field and a longitudinal
magnetic field; according to the testing requirements of the
transverse magnetic field and the longitudinal
magnetic field, a
copper screen position is determined with the assistance of coordinate lines; the
copper screen is immersed in the dispersion liquid, and is stood for 1min; the
copper screen is drawn back, and is dried on a sealing membrane. Because of the high adsorption capacity of the magnetic particles, a single-layer magnetic particle
chain structure is picked up by the copper screen, such that the transmission
electron microscope observation sample of the magnetic liquid in the
transverse magnetic field or the longitudinal magnetic field is prepared. The sample is delivered to a transmission
electron microscope observation room, and the distribution state and arrangement condition of the magnetic particles in the
transverse magnetic field or the longitudinal magnetic field can be observed.