本文主要研究内容
作者赵慧（2019）在《MgTiO3：Fe（Co）薄膜的光学和磁学性质研究》一文中研究指出：近年来,微波器件的小型化和集成化对介质材料的损耗、介电常数和稳定性等提出了更高的要求。钛铁矿结构的MgTiO3,具有低损耗、高介电常数和良好稳定性等特点,而成为一种新型的微波介电材料。为了进一步地改善和提高其微波介电性,文献中报道了不同形式的MgTiO3样品,如块体、粉末以及薄膜等。许多研究发现,纯六方相MgTiO3不易获得,但是通过一些元素的掺杂可以降低其烧结温度以及改善相纯度,进而改善MgTiO3的微波介电性。人们虽然对MgTiO3开展了许多研究,但是还有一些问题没有解决:如报道的MgTiO3的光学带隙相差很大,造成这种现象的原因是什么,目前还没有人给出合理的解释;MgTiO3薄膜的光学研究缺乏系统性;磁性元素掺杂MgTiO3薄膜的研究还很匮乏等。鉴于MgTiO3研究中存在的问题,我们开展了磁性元素掺杂MgTiO3薄膜的制备、结构表征、磁学和光学性质的研究。另外,铁基硫属元素化合物FeX2（X=S,Se,Te）,由于其优异的性能,例如窄带隙,高的载流子迁移率,在可见光区和紫外光区具有大的吸收系数等而引起广泛关注。特别是具有白铁矿结构的FeTe2,以其半导体行为和顺磁性而引起关注。鉴于FeTe2的相关研究很少,而且Fe位掺杂可能会改变FeTe2的结构而出现新的物性,我们制备了Co掺杂FeTe2单晶,并对其结构和电输运进行了初步的研究。在论文中,我们采用溶胶凝胶法（sol-gel）制备了Fe、Co掺杂MgTiO3薄膜,以及自助熔剂法生长了Co掺杂FeTe2单晶,开展了一些工作。主要内容如下:1.我们通过溶胶凝胶法在Si衬底上制备出Fe掺杂MgTiO3薄膜。X射线衍射（XRD）结果表明,所有样品的空间群为R-3,属于六方晶系,是纯相的钛铁矿结构。随着Fe浓度从0.00增加到0.07,晶格参数a与c均逐渐增加,这表明Fe掺杂改变了MgTiO3的晶体结构。样品的X射线光电子能谱结果表明,样品中存在Fe3+离子。依据Tauc-Lorentz介电函数模型,对Fe掺杂MgTiO3薄膜在240-825nm范围的椭圆偏振谱进行处理,来研究样品的光学性质。样品在532nm处的折射率n随着Fe掺杂的增加呈现出先增大后减小的行为,薄膜的光学带隙EOBG随着Fe掺杂量x的增加,从4.55 eV降低到4.36 eV,满足关系式EOBG=（4.55-2.67*x）,这与Fe掺杂引起的杂质带有关。样品的室温磁化强度-磁场（M-H）测量表明,未掺杂MgTiO3薄膜呈现出的弱磁性可能源于氧空位。x=0.01的样品显示出明显的铁磁性。随着Fe掺杂量增加,样品的磁性越来越强,同时也发现当Fe掺杂量x>0.01时,样品在高场下表现出不饱和磁化特性。Fe3+-VO-Fe3+之间的交换以及束缚磁极化子的铁磁性和两个Fe3+间的反铁磁性的共存与竞争导致了Fe掺杂MgTiO3薄膜的复杂磁行为。另外,我们对生长在石英衬底上的Fe掺杂MgTiO3薄膜进行紫外-可见-近红外透射测量,结果表明随着Fe掺杂浓度的增加,薄膜的吸收边呈现出红移现象。2.采用溶胶凝胶法来制备Co掺杂MgTiO3薄膜。薄膜的XRD结果表明,所有薄膜样品均为六方相,其空间群为R-3（148）。室温M-H测量表明未掺杂的MgTiO3薄膜表现出很弱的铁磁有序,但随着Co掺杂浓度的增加,MgTiO3薄膜的铁磁性逐渐增强,并且随着磁场的增加所有样品表现出磁饱和现象。对于掺杂浓度x=0,0.01,0.03,0.05,0.07的样品,饱和磁化强度值分别为0.04 emu/cm3,1.15 emu/cm3,2.24 emu/cm3,3.28emu/cm3,4.49 emu/cm3。另外,我们还生长了石英衬底上Co掺杂MgTiO3薄膜。从样品的透射谱可以看出,薄膜的基本吸收边出现了红移。利用Cauchy色散模型,对样品在600-1200nm之间的透射谱进行处理,研究了其折射率n和消光系数k。随着Co含量的增加,样品在1150nm处的折射率和在860nm处的消光系数都逐渐增大,这意味着Co掺杂明显改变了样品的光学性质。3.利用自助熔剂法制备了名义组分的Fe1-xCoxTe2（x=0.2,0.3,0.4,0.5）单晶。XRD分析表明单晶具有正交结构,空间群为Pnnm（58）。共焦显微激光拉曼光谱测试结果表明单晶约在90.348 cm-1、120.56 cm-1、140.7 cm-1处显示出明显的拉曼峰。名义组分为Fe0.5Co0.5Te2的样品的电输运表现为类金属行为,利用Bloch-Grüneisen理论对其电输运进行研究,结果表明导电性可能来源于带内电子跃迁。
Abstract
jin nian lai ,wei bo qi jian de xiao xing hua he ji cheng hua dui jie zhi cai liao de sun hao 、jie dian chang shu he wen ding xing deng di chu le geng gao de yao qiu 。tai tie kuang jie gou de MgTiO3,ju you di sun hao 、gao jie dian chang shu he liang hao wen ding xing deng te dian ,er cheng wei yi chong xin xing de wei bo jie dian cai liao 。wei le jin yi bu de gai shan he di gao ji wei bo jie dian xing ,wen suo zhong bao dao le bu tong xing shi de MgTiO3yang pin ,ru kuai ti 、fen mo yi ji bao mo deng 。hu duo yan jiu fa xian ,chun liu fang xiang MgTiO3bu yi huo de ,dan shi tong guo yi xie yuan su de can za ke yi jiang di ji shao jie wen du yi ji gai shan xiang chun du ,jin er gai shan MgTiO3de wei bo jie dian xing 。ren men sui ran dui MgTiO3kai zhan le hu duo yan jiu ,dan shi hai you yi xie wen ti mei you jie jue :ru bao dao de MgTiO3de guang xue dai xi xiang cha hen da ,zao cheng zhe chong xian xiang de yuan yin shi shen me ,mu qian hai mei you ren gei chu ge li de jie shi ;MgTiO3bao mo de guang xue yan jiu que fa ji tong xing ;ci xing yuan su can za MgTiO3bao mo de yan jiu hai hen kui fa deng 。jian yu MgTiO3yan jiu zhong cun zai de wen ti ,wo men kai zhan le ci xing yuan su can za MgTiO3bao mo de zhi bei 、jie gou biao zheng 、ci xue he guang xue xing zhi de yan jiu 。ling wai ,tie ji liu shu yuan su hua ge wu FeX2（X=S,Se,Te）,you yu ji you yi de xing neng ,li ru zhai dai xi ,gao de zai liu zi qian yi lv ,zai ke jian guang ou he zi wai guang ou ju you da de xi shou ji shu deng er yin qi an fan guan zhu 。te bie shi ju you bai tie kuang jie gou de FeTe2,yi ji ban dao ti hang wei he shun ci xing er yin qi guan zhu 。jian yu FeTe2de xiang guan yan jiu hen shao ,er ju Fewei can za ke neng hui gai bian FeTe2de jie gou er chu xian xin de wu xing ,wo men zhi bei le Cocan za FeTe2chan jing ,bing dui ji jie gou he dian shu yun jin hang le chu bu de yan jiu 。zai lun wen zhong ,wo men cai yong rong jiao ning jiao fa （sol-gel）zhi bei le Fe、Cocan za MgTiO3bao mo ,yi ji zi zhu rong ji fa sheng chang le Cocan za FeTe2chan jing ,kai zhan le yi xie gong zuo 。zhu yao nei rong ru xia :1.wo men tong guo rong jiao ning jiao fa zai Sichen de shang zhi bei chu Fecan za MgTiO3bao mo 。Xshe xian yan she （XRD）jie guo biao ming ,suo you yang pin de kong jian qun wei R-3,shu yu liu fang jing ji ,shi chun xiang de tai tie kuang jie gou 。sui zhao Fenong du cong 0.00zeng jia dao 0.07,jing ge can shu ayu cjun zhu jian zeng jia ,zhe biao ming Fecan za gai bian le MgTiO3de jing ti jie gou 。yang pin de Xshe xian guang dian zi neng pu jie guo biao ming ,yang pin zhong cun zai Fe3+li zi 。yi ju Tauc-Lorentzjie dian han shu mo xing ,dui Fecan za MgTiO3bao mo zai 240-825nmfan wei de tuo yuan pian zhen pu jin hang chu li ,lai yan jiu yang pin de guang xue xing zhi 。yang pin zai 532nmchu de she she lv nsui zhao Fecan za de zeng jia cheng xian chu xian zeng da hou jian xiao de hang wei ,bao mo de guang xue dai xi EOBGsui zhao Fecan za liang xde zeng jia ,cong 4.55 eVjiang di dao 4.36 eV,man zu guan ji shi EOBG=（4.55-2.67*x）,zhe yu Fecan za yin qi de za zhi dai you guan 。yang pin de shi wen ci hua jiang du -ci chang （M-H）ce liang biao ming ,wei can za MgTiO3bao mo cheng xian chu de ruo ci xing ke neng yuan yu yang kong wei 。x=0.01de yang pin xian shi chu ming xian de tie ci xing 。sui zhao Fecan za liang zeng jia ,yang pin de ci xing yue lai yue jiang ,tong shi ye fa xian dang Fecan za liang x>0.01shi ,yang pin zai gao chang xia biao xian chu bu bao he ci hua te xing 。Fe3+-VO-Fe3+zhi jian de jiao huan yi ji shu fu ci ji hua zi de tie ci xing he liang ge Fe3+jian de fan tie ci xing de gong cun yu jing zheng dao zhi le Fecan za MgTiO3bao mo de fu za ci hang wei 。ling wai ,wo men dui sheng chang zai dan ying chen de shang de Fecan za MgTiO3bao mo jin hang zi wai -ke jian -jin gong wai tou she ce liang ,jie guo biao ming sui zhao Fecan za nong du de zeng jia ,bao mo de xi shou bian cheng xian chu gong yi xian xiang 。2.cai yong rong jiao ning jiao fa lai zhi bei Cocan za MgTiO3bao mo 。bao mo de XRDjie guo biao ming ,suo you bao mo yang pin jun wei liu fang xiang ,ji kong jian qun wei R-3（148）。shi wen M-Hce liang biao ming wei can za de MgTiO3bao mo biao xian chu hen ruo de tie ci you xu ,dan sui zhao Cocan za nong du de zeng jia ,MgTiO3bao mo de tie ci xing zhu jian zeng jiang ,bing ju sui zhao ci chang de zeng jia suo you yang pin biao xian chu ci bao he xian xiang 。dui yu can za nong du x=0,0.01,0.03,0.05,0.07de yang pin ,bao he ci hua jiang du zhi fen bie wei 0.04 emu/cm3,1.15 emu/cm3,2.24 emu/cm3,3.28emu/cm3,4.49 emu/cm3。ling wai ,wo men hai sheng chang le dan ying chen de shang Cocan za MgTiO3bao mo 。cong yang pin de tou she pu ke yi kan chu ,bao mo de ji ben xi shou bian chu xian le gong yi 。li yong Cauchyse san mo xing ,dui yang pin zai 600-1200nmzhi jian de tou she pu jin hang chu li ,yan jiu le ji she she lv nhe xiao guang ji shu k。sui zhao Cohan liang de zeng jia ,yang pin zai 1150nmchu de she she lv he zai 860nmchu de xiao guang ji shu dou zhu jian zeng da ,zhe yi wei zhao Cocan za ming xian gai bian le yang pin de guang xue xing zhi 。3.li yong zi zhu rong ji fa zhi bei le ming yi zu fen de Fe1-xCoxTe2（x=0.2,0.3,0.4,0.5）chan jing 。XRDfen xi biao ming chan jing ju you zheng jiao jie gou ,kong jian qun wei Pnnm（58）。gong jiao xian wei ji guang la man guang pu ce shi jie guo biao ming chan jing yao zai 90.348 cm-1、120.56 cm-1、140.7 cm-1chu xian shi chu ming xian de la man feng 。ming yi zu fen wei Fe0.5Co0.5Te2de yang pin de dian shu yun biao xian wei lei jin shu hang wei ,li yong Bloch-Grüneisenli lun dui ji dian shu yun jin hang yan jiu ,jie guo biao ming dao dian xing ke neng lai yuan yu dai nei dian zi yue qian 。
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论文详细介绍
论文作者分别是来自河南大学的赵慧，发表于刊物河南大学2019-09-20论文，是一篇关于薄膜论文,掺杂论文,光学性质论文,磁学性质论文,电学性质论文,河南大学2019-09-20论文的文章。本文可供学术参考使用，各位学者可以免费参考阅读下载，文章观点不代表本站观点，资料来自河南大学2019-09-20论文网站，若本站收录的文献无意侵犯了您的著作版权，请联系我们删除。