Mn、F共掺杂ZrO2/HfO2磁性及其氧空位控制研究

Within all the doped ZrO2/HfO2 ceramic systems, Mn-doped ZrO2/HfO2 have the simplist structures and special physical properties, such as optical,electrical, magnetic, thermotic, mechanical and chemical properties. Since the report of the ferromagnetic property of Mn doped ZrO2 thin film by Hong et al in 2012, transition metal ions doped ZrO2/HfO2 based dilute magnetic semiconductors show great potentials and offered more opportunities for practical applications. However, the study of Mn doped ZrO2/HfO2 is still under the beginning level,and some basal problems (such as phase transiton and magnetic transformation mechanics) are still unknown. In our study, solid state reaction and sol gel-hydre thermal methods will be adopted to fabricate Mn and F codoped ZrO2/HfO2. With the optimization process ,the relationship among element stoichiometric proportion, phase composition, valence state, defect concentration, phase transion and magnetic transforamtion will be systematically discussed. The relationship between heat treatment and magnetic will be expounded. And fluornion ions will be introduced in the Mn doped ZrO2/HfO2 crystal lattice to study the effect on the defect concentration. And finally, base on the front studies, the oxygen vacancy control ablity and magnetic transformation progress will be profounded represented. The study of this project will not only obtain specific magnetic property and valence controllable Mn doped ZrO2/HfO2 ceramics for practical applications, but also built the theoretical and experimental basis for the further developments and applications.

Mn掺杂ZrO2和Mn掺杂HfO2被认为是具有潜在应用前景的多功能材料，特别是室温铁磁性Mn掺杂ZrO2薄膜的发现，为ZrO2基稀磁半导体的发展及应用提供了新的机遇。目前实用化Mn掺杂ZrO2/HfO2磁性半导体的研究尚处于初级阶段，相关磁性来源等基础问题尚未明确。本项目在选择固相反应和溶胶凝胶-水热法制备Mn、F共掺杂ZrO2/HfO2材料基础上，通过优化工艺，建立掺杂配比、相组成、Mn元素价态、缺陷浓度等因素与磁性转变之间的对应关系，阐述不同热处理条件对磁性的影响，并通过研究F-的引入对Mn掺杂ZrO2/HfO2体系中缺陷的影响，探讨F-对氧空位的调控作用，从而揭示Mn、F共掺杂ZrO2/HfO2结构转变及磁性机制。本项目研究为制备Mn掺杂ZrO2/HfO2室温铁磁性材料的开发和应用奠定理论和实验基础。

Mn掺杂ZrO2和Mn掺杂HfO2被认为是具有潜在应用前景的多功能材料，特别是室温铁磁性Mn掺杂ZrO2薄膜的发现，为ZrO2基稀磁半导体的发展及应用提供了新的机遇。本项目针对实用化Mn掺杂ZrO2/HfO2磁性半导体的研究尚处于初级阶段，相关磁性来源等基础问题尚未明确的研究现状，采用固相反应及溶胶凝胶—水热法制备Mn、F共掺杂ZrO2/HfO2陶瓷及粉体材料。研究表明，无论采用何种制备手段，Mnx+起稳定剂的作用，能使ZrO2/HfO2维持立方相结构；F-起调控氧空位数量的作用，增大F-掺杂浓度，会降低氧空位的数量，使ZrO2/HfO2发生立方相→单斜相相变。同时，对于湿化学方法合成的Mn、F共掺杂ZrO2粉体，F-不仅起到调控氧空位数量的作用，还起到调控晶体生长形貌，促进晶体生长的作用。Mn、F共掺杂ZrO2/HfO2材料的磁性能随制备手段的不同而有所差异。首先，针对于ZrO2陶瓷材料而言，未经F-掺杂的立方相Mn稳定ZrO2陶瓷材料，在零场冷却的条件下发生抗磁—顺磁性转变，而在有场冷却的条件下呈铁磁—顺磁性转变规律；O2退火处理后的单斜相Mn稳定ZrO2陶瓷材料的磁性转变规律与退火前样品一致，但矫顽力和剩余磁化强度大幅增加，磁性转变温度Tc~50K；经F-掺杂后的Mn稳定ZrO2陶瓷材料，零场冷及场冷条件下均发生亚铁磁—顺磁转变。其次，对于ZrO2粉体而言，未经F-掺杂时，粉体呈铁磁—顺磁转变；掺杂F-后，粉体的铁磁性明显减弱，磁性转变温度Tc低于20K。第三，对于HfO2陶瓷材料而言，其磁性转变规律较ZrO2更复杂，单斜相HfO2随温度升高发生铁磁—反铁磁—顺磁转变，转变温度分别为75K和122K。最后，以NaBF4为矿化剂水热法可以得到多形貌、单分散的ZrO2粉体，该粉体具有优异的发光特性。本项目研究为制备Mn掺杂ZrO2/HfO2铁磁性材料的开发和应用奠定理论和实验基础，对于阐明ZrO2/HfO2基稀磁半导体磁性起源的认识有重要意义，为特殊形貌ZrO2材料的开发与利用提供了新的思路。