The Influence Of Magnetic Heat Treatment On Properties Of Magnetic Materials

This thesis consists of two parts, in the first part, we prepared the FeNi alloy films using electrodeposition techniques and we studied the effects of magnetic heat treatment on the films, in the second part, we prepared the NiZn ferrite thin films by the sol-gel method and we studied the effects of magnetic heat treatment on the flims. The FeNi alloy film prepared by electroplating process and we studied the effect of the magnetic field heat treatment on the film at different temperatures in-plane to induce uniaxial anisotropy to enhanced the ferromagnetic resonance frequency. In the second part, we focus on the effect of process parameters and annealing process on properties of NiZn ferrite films, the magnetic heat treatment was also studied at different temperatures, different times.We fixed the composition of the solution and the deposition time when we prepared the Fe-Ni alloy films through direct current electrodeposition. We studied the effect of different deposition voltages and processing of the films and the magnetic heat treatment was also studied. We get the following conclusions:1. The film annealed at 300℃under external magnetic field of 3000 Oe has most obvious uniaxial anisotropy in the film plane. The ferromagnetic resonance frequency of the anisotropic film is 1.15 GHz and it is far greater than that of the as-electrodeposited film (780 MHz).2. The film deposited under a magnetic field of 800 Oe has an obvious uniaxial anisotropy, but, the effect of magnetic heat treatment is not obvious.Nickel zinc ferrite (Nio.4Zno.6Fe204) films on Si (100) substrate were synthesized using a spin-coating method. We get the following conclusions:1. With the increase of annealing temperature, the saturation magnetization Ms increases in the temperature ranging from 400 to 700℃, however, decreases above 700℃, and the coercivity Hc increases in the temperature ranging from 400 to 800℃, decreases above 800℃. After annealed at 700℃for 2 h in air with the heating rate 2℃/min, the film shows a maximum saturation magnetization Ms of 349 emu/cc and low coercivity Hc of 66 Oe. The Ms of Nio.4Zno.6Fe204 films annealed at 700℃increases with increasing annealing time and the Hc changes slightly.2. It is difficult to induce the uniaxial anisotropy of the NiZn ferrite thin films under magnetic heat treatment at different times and temperatures.