The invention provides a preparation method of magnetic nanometer particles with the adjustable and controllable particle
diameter. According to the preparation method, a chemical
thermal decomposition method is adopted, firstly, organic substances and partial or all
metal precursors are mixed to take complex reaction so that at least partial
metal precursors take the complex reaction with the organic substances, the
decomposition speed of the partial
metal precursors in the subsequent chemical
thermal decomposition reaction is changed, then,
mixed solution subjected to the complex reaction is mixed with reaction solvents, the rest metal precursors and
surface active agents to form a
reaction system, the temperature of the
reaction system is raised for carrying out the chemical
thermal decomposition reaction, the constant-temperature maintaining and the
centrifugal separation are carried out after the reaction, and the magnetic nanometer particles are obtained. The method has the advantages that only the consumption of the organic substances participating in the complex reaction needs to be regulated, other
reaction conditions are maintained unchanged, the regulation and the control of the particle
diameter of the magnetic nanometer particles can be realized, and in addition, the regulation and control range can reach 0.5nm, so the invention belongs to the preparation method of the magnetic nanometer particles with the adjustable and controllable particle
diameter, and good application prospects are realized.