本文選題：多鐵 + 微波　； 參考：《山東大學(xué)》2015年碩士論文

【摘要】：多鐵性材料是同時具有兩個或者兩個以上基本鐵性,且這些鐵性之間可能通過某些效應(yīng)可以實現(xiàn)相互轉(zhuǎn)換的功能,在信息存儲、傳感器等領(lǐng)域有著廣闊的應(yīng)用前景。人們通過對多鐵性材料的磁、電、熱力學(xué)等基本性質(zhì)的研究發(fā)現(xiàn)其存在多種長程有序,并且相互耦合。其中最近某些單相多鐵材料的磁電耦合效應(yīng)方面取得了很大的突破。另一方面,由磁性材料和鐵電材料構(gòu)造而成的層狀多鐵異質(zhì)結(jié)構(gòu)因其在磁電耦合效應(yīng)方面的重要性也逐漸成為研究的熱點。研究此結(jié)構(gòu)的關(guān)鍵所在就是利用磁電耦合效應(yīng)來實現(xiàn)外加電場對器件的磁性的調(diào)控。這種結(jié)構(gòu)的研究不但對鐵磁、鐵電相互耦合作用的微觀機(jī)制有著深遠(yuǎn)的意義,而且在未來自旋電子學(xué)器件的領(lǐng)域有著廣闊的應(yīng)用前景。本文從單相多鐵材料GdFeO3出發(fā),逐漸將研究過渡到層狀多鐵材料的磁電可調(diào)特性,通過外加電場可以誘導(dǎo)層狀多鐵材料的磁電特性。具體工作如下：通過溶膠凝膠法(Sol-Gel)制備GdFeO3納米粉體材料,采用XRD表征物相結(jié)構(gòu),掃描電子顯微鏡分析其表面形貌和顆粒大小。800℃燒結(jié)的GdFeO3樣品物相最純。在室溫下,GdFeO3樣品具有反鐵磁性,其飽和磁場強(qiáng)度為0.5emu/g,飽和磁化磁場為1850e。室溫下,通過矢量網(wǎng)絡(luò)分析儀測量樣品的電磁參數(shù)隨頻率的變化發(fā)現(xiàn)其呈現(xiàn)共振型頻譜；厚度為3mm的環(huán)狀樣品的吸波性能最優(yōu)。采用直流磁控濺射法制備的坡莫合金薄膜,經(jīng)過不同襯底溫度以及不同角度濺射,得到具有不同飽和磁場強(qiáng)度和不同自然磁共振頻率的樣品。實驗表明：襯底溫度較低時的FeNi合金薄膜具有更高的單軸各向異性場,并且其共振頻率較襯底溫度600℃的樣品大約0.6GHz。伴隨著磁控濺射樣品架彎曲角度的不同,所制備出的樣品具有不同的矯頑力和飽和磁場強(qiáng)度以及不同的自然磁共振頻率。因此可以利用鍍膜過程中采用不同濺射角度或者襯底溫度來制備出我們所需求得電磁參數(shù)的樣品。這對研究FeNi和FeCo合金薄膜在微波高頻電子器件領(lǐng)域具有很好的應(yīng)用前景。分別采用磁控濺射和脈沖激光沉積法(PLD)制備FeCo/PMN-PT以及YIG/PMN-PT層狀多鐵材料。通過控制外電場誘導(dǎo)其共振頻率發(fā)生漂移以及靜磁能發(fā)生改變,YIG/PMN-PT的自然共振頻率漂移大小約為0.1GHz/kv。 FeCo/PMN-PT漂移速率約為80MHz/kv。這表明通過外加電場可以顯著提高層狀多鐵異質(zhì)結(jié)構(gòu)的飽和磁化強(qiáng)度以及共振頻率,且有磁化強(qiáng)度在面內(nèi)方向隨電場變化較為明顯。這種層狀多鐵材料的磁電耦合效應(yīng)在通信領(lǐng)域的高頻微波器件具有很好的應(yīng)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，

本文編號：1991294