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磁场热处理对磁性材料性能的影响

The Influence of Magnetic Heat Treatment on Properties of Magnetic Materials

【作者】 袁涛

【导师】 刘青芳;

【作者基本信息】 兰州大学 , 凝聚态物理, 2011, 硕士

【摘要】 本论文主要分为两部分,第一部分是用电镀法制备FeNi合金薄膜和磁场热处理对它的影响;第二部分是采用溶胶-凝胶(sol-gel)旋转涂层工艺制备NiZn铁氧体薄膜并对其磁场热处理。第一部分电镀法制备FeNi合金薄膜并对其磁场热处理,论文在制备FeNi合金薄膜时固定了溶液的成份和沉积时间,研究了直流沉积时不同沉积电压和加外磁场下对样品形貌和磁性的影响,也研究了在不同温度下磁场热处理对其面内单轴各向异性的诱导,来提高共振频率,从而探索提高它的高频应用。得出以下结论:1、在相同的沉积时间600 s,沉积电压分别为0.6 V,0.8 V,1.0 V下沉积的FeNi合金薄膜,0.6 V下沉积的薄膜饱和磁化强度Ms最高,为998emu/cc,且矫顽力Hc为9 Oe。在对样品进行磁场热处理发现,制备的FeNi合金薄膜面内不同方向的矫顽力Hc发生了变化,饱和磁化强度Ms有所增大,并且它们的共振频率fr石得到了不同程度的提高,磁场热处理效果明显。2、在沉积薄膜时加一定的外磁场发现,薄膜具有明显的面内单轴各向异性。在磁场热处理下,它的面内单轴各向异性有所变化,在300℃磁场热处理下各向异性场有所增加,但是在高温下有所降低。第二部分采用溶胶-凝胶(sol-gel)旋转涂层工艺制备NiZn铁氧体薄膜并对其磁场热处理,论文在溶胶配制、甩胶及退火工艺方面对NiZn铁氧体薄膜的性能进行了研究,同时研究了磁场热处理对它的影响,得出以下结论:1、制备的NiZn铁氧体薄膜在不同温度热处理下,通过XRD研究发现随着温度的升高结晶能变好,700℃下处理的样品结晶性最好,从VSM可以看出Hc都普遍很小,Ms先增大后减小,最大值为349emu/cc。由SEM图可以看出薄膜颗粒大小均匀,厚度为386 nm,颗粒大小为30 nm左右。2、在不同温度和不同时间下对制备的NiZn铁氧体薄膜进行磁场热处理发现,对铁氧体的诱导效果不明显,而且在诱导过程中会导致矫顽力Hc的增大,降低软磁性能。

【Abstract】 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.

  • 【网络出版投稿人】 兰州大学
  • 【网络出版年期】2011年 11期
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