基于磁性材料的微波器件的研究

发布时间：2018-06-07 13:12

  本文选题：多铁 + 微波　； 参考：《山东大学》2015年硕士论文

【摘要】：多铁性材料是同时具有两个或者两个以上基本铁性,且这些铁性之间可能通过某些效应可以实现相互转换的功能,在信息存储、传感器等领域有着广阔的应用前景。人们通过对多铁性材料的磁、电、热力学等基本性质的研究发现其存在多种长程有序,并且相互耦合。其中最近某些单相多铁材料的磁电耦合效应方面取得了很大的突破。另一方面,由磁性材料和铁电材料构造而成的层状多铁异质结构因其在磁电耦合效应方面的重要性也逐渐成为研究的热点。研究此结构的关键所在就是利用磁电耦合效应来实现外加电场对器件的磁性的调控。这种结构的研究不但对铁磁、铁电相互耦合作用的微观机制有着深远的意义,而且在未来自旋电子学器件的领域有着广阔的应用前景。本文从单相多铁材料GdFeO3出发,逐渐将研究过渡到层状多铁材料的磁电可调特性,通过外加电场可以诱导层状多铁材料的磁电特性。具体工作如下：通过溶胶凝胶法(Sol-Gel)制备GdFeO3纳米粉体材料,采用XRD表征物相结构,扫描电子显微镜分析其表面形貌和颗粒大小。800℃烧结的GdFeO3样品物相最纯。在室温下,GdFeO3样品具有反铁磁性,其饱和磁场强度为0.5emu/g,饱和磁化磁场为1850e。室温下,通过矢量网络分析仪测量样品的电磁参数随频率的变化发现其呈现共振型频谱；厚度为3mm的环状样品的吸波性能最优。采用直流磁控溅射法制备的坡莫合金薄膜,经过不同衬底温度以及不同角度溅射,得到具有不同饱和磁场强度和不同自然磁共振频率的样品。实验表明：衬底温度较低时的FeNi合金薄膜具有更高的单轴各向异性场,并且其共振频率较衬底温度600℃的样品大约0.6GHz。伴随着磁控溅射样品架弯曲角度的不同,所制备出的样品具有不同的矫顽力和饱和磁场强度以及不同的自然磁共振频率。因此可以利用镀膜过程中采用不同溅射角度或者衬底温度来制备出我们所需求得电磁参数的样品。这对研究FeNi和FeCo合金薄膜在微波高频电子器件领域具有很好的应用前景。分别采用磁控溅射和脉冲激光沉积法(PLD)制备FeCo/PMN-PT以及YIG/PMN-PT层状多铁材料。通过控制外电场诱导其共振频率发生漂移以及静磁能发生改变,YIG/PMN-PT的自然共振频率漂移大小约为0.1GHz/kv。 FeCo/PMN-PT漂移速率约为80MHz/kv。这表明通过外加电场可以显著提高层状多铁异质结构的饱和磁化强度以及共振频率,且有磁化强度在面内方向随电场变化较为明显。这种层状多铁材料的磁电耦合效应在通信领域的高频微波器件具有很好的应用前景。
[Abstract]:Polyferric materials have two or more basic iron properties at the same time, and these irons may be able to convert each other through some effects, so they have a broad application prospect in the field of information storage, sensors and other fields. Through the study of magnetic, electric and thermodynamic properties of ferromagnetic materials, it is found that there are many kinds of long term order and coupling among them. Recently, a great breakthrough has been made in the magnetoelectric coupling effect of some single phase multi-iron materials. On the other hand, layered multi-iron heterostructures constructed from magnetic and ferroelectric materials have gradually become the focus of research because of their importance in magnetoelectric coupling effect. The key to study this structure is to use the magnetoelectric coupling effect to realize the magnetic regulation of the device by the external electric field. The study of this structure is not only of great significance to the micro mechanism of ferromagnetic and ferroelectric interaction, but also has a broad application prospect in the field of spin electronics in the future. In this paper, the magnetoelectric tunability of single phase multiferroelectric material (GdFeO3) is studied gradually, and the magnetoelectric properties of layered polyferric material can be induced by applied electric field. The main work is as follows: GdFeO3 nanocrystalline powders were prepared by sol-gel method. The phase structure was characterized by XRD. The surface morphology and particle size of GdFeO3 samples sintered at .800 鈩，

本文编号：1991294