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| Abstract: |
| Diluted magnetic oxides have evolved into a popular branch of materials science during the last decade. In the first few years, people attributed the ferromagnetism to the magnetic dopants. However, the observation of ferromagnetism in undoped HfO2 thin films made it more controversial and promoted extensive research on the ferromagnetism in various undoped oxides. Both of the experimental works and theoretical studies have shown that intrinsic defects in oxide nanomaterials play a crucial role in the origin of such an unexpected ferromagnetism, in spite of some contradicting views which kind of defects is predominant. In the past several years, we have conducted systematic and thorough research on the room temperature ferromagnetism in undoped ZrO2 thin films, and clarify some physics behind it. We firstly prepared undoped ZrO2 thin films by different ways, such as Pulsed electron beam deposition, magnetron sputtering, and electron beam evaporation, and successfully obtained ZrO2 thin films with different crystalline structure, in particular a pure high-temperature stabilized one, by adjusting some preparation parameters during the deposition process or post-annealing treatment. A phase-dependent ferromagnetism was then confirmed to exist in such ZrO2 thin films. Further, we conducted exhaustive defect analysis and characterization by X-ray photoelectron spectroscopy, photoluminescence spectra, and electron paramagnetic resonance, respectively, and found the oxygen vacancy, specifically the single ionized oxygen vacancy (VO+), has a remarkable influence on the enhancement of ferromagnetism. Herein, we will review the work in detail on the phase-dependent and oxygen vacancy-enhanced room temperature ferromagnetism in undoped ZrO2 thin films. |
| Key words: ZrO2 thin film ferromagnetism phase-dependent oxygen vacancy |
| DOI：10.11916/j.issn.1005-9113.2017.01.001 |
| Clc Number:O484.1 |
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| Descriptions in Chinese: |
| 未掺杂氧化锆薄膜的铁磁性研究 宁帅，张政军 （清华大学材料学院） 创新点说明：1，通过不同的物理气相沉积方法，实现了对未掺杂氧化锆薄膜的物相调控；2，发现了未掺杂氧化锆薄膜室温铁磁性对物相结构的依赖性；3，通过缺陷分析表征，发现四方相氧化锆的室温铁磁性主要由氧空位缺陷调控。 研究目的： 未掺杂氧化锆薄膜的制备、物相和缺陷调控以及室温铁磁性研究。 研究方法： 脉冲电子束沉积、直流反应磁控溅射、电子束蒸镀。 结果： 1，通过不同的物理气相沉积方法，实现了未掺杂氧化锆薄膜的物相调控；2，发现了未掺杂氧化锆薄膜室温铁磁性的物相依赖性；3，通过缺陷分析表征，发现四方相氧化锆的室温铁磁性主要由氧空位缺陷调控。 结论： 1，制备了不同物相结构的未掺杂的氧化锆薄膜；2，发现了四方相氧化锆薄膜可以在室温下呈现铁磁性；3，四方相氧化锆薄膜中的室温铁磁性主要由氧空位缺陷引起。 关键词：氧化锆薄膜，物相调控，室温铁磁性，氧空位缺陷 |
