The Study Of Microwave Device Based On Magnetic Materials

Multiferroic materials, which simultaneously have two or more ferroic orders and the coupling interaction between the different oeder parameters could have new effects. People through the study of the basic properties of multiferroic materials, magnetic, electrical, thermal, etc. found that there are many long-range order, and mutual coupling. The most recent magnetic coupling effect of certain single-phase multiferroic material has made great breakthrough. On the other hand, construction of a magnetic material and a ferroelectric material made of layered multiferroic heterostructures its importance in terms of magnetic coupling effect has become a hot research. Key to this is the use of the structure where the magnetic coupling effect of the applied electric field to achieve magnetic device regulation. Study the structure of not only ferromagnetic, ferroelectric mutual coupling of microscopic mechanisms of profound significance, but also in the field of future spintronic device has broad application prospects. From the single-phase multiferroic material GdFeO3 starting gradually transition to study magnetic layer multiferroic material adjustable features, by applying a magnetic field can induce electrical properties of layered multiferroic materials. Details of this thesis are as follows:We prepared GdFeO3 nanopowders by sol-gel method (Sol-Gel), and did phase structure characterized by XRD, scanning electron microscopy analysis of surface morphology and particle size. We find when sintering at 900 ℃ GdFeO3 has the purest phase. At room temperature, GdFeO3 antiferromagnetic samples have a saturation magnetization 0.5emu/g, the saturation magnetic field is about 185Oe. At room temperature by the electromagnetic parameters of the vector network analyzer to measure the change in frequency of the sample was found to exhibit resonance spectrum; the optimal thickness of the annular sample absorbing properties of 3mm.We prepared permalloy thin film by using DC magnetron sputtering through different substrate temperature and sputtering different angles, to obtain samples having different saturation magnetization and the magnetic resonance frequency of different nature. Experimental results show that:the substrate temperature is 700℃ of FeNi alloy film has higher uniaxial anisotropy field, and its resonant frequency than the sample substrate temperature of 350 ℃ approximately 0.6GHz. With various sputtering bending angle sample holder, sample prepared with different coercively and saturation magnetization and the magnetic resonance frequency different from the natural. So we can use different sputter coating process using angle or the substrate temperature to prepare the electromagnetic parameters obtained samples of what we need. In a word, FeNi and FeCo nanocrystalline thin films of electronic devices in the field of high-frequency microwave could have a good prospect.We prepared FeCo/PMN-PT and YIG/PMN-PT layer multiferroic materials respectively by magnetron sputtering and pulsed laser deposition (PLD). We find that we could control the resonant frequency drift induced by electric field. The magnetic resonance of YIG/PMN-PT drift size is about 0.1 GHz/kv. While FeCo/PMN-PT drift rate of about 80MHz/kv. This phenomenon indicates that the electric field can significantly increase the magnetization of iron heterostructure multi-layered, and the resonant frequency, and there is in-plane magnetization direction changes with the electric field more obvious. After the magnetic field is removed the magnetization multiferroic layered structure of the material hardly changed, the display having a memory effect. Magnetic coupling effect of this multi-layered iron materials in the field of high-frequency microwave communications devices have good prospects.