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铁磁性坡莫合金纳米环的制备与磁性研究
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作者 曾帅 郭振刚 潘礼庆 《材料导报》 EI CAS CSCD 北大核心 2013年第16期21-23,42,共4页
铁磁性纳米环是一种纳米尺寸的环状实体,由于具备高密度磁存储的能力,被认为是下一代高性能存储器——磁随机存储器(MRAM)的重要结构单元。利用聚苯乙烯微球模板法制备了单分散的坡莫合金Ni75Fe25(NiFe)纳米环,并用扫描电子显微镜(SEM)... 铁磁性纳米环是一种纳米尺寸的环状实体,由于具备高密度磁存储的能力,被认为是下一代高性能存储器——磁随机存储器(MRAM)的重要结构单元。利用聚苯乙烯微球模板法制备了单分散的坡莫合金Ni75Fe25(NiFe)纳米环,并用扫描电子显微镜(SEM)表征了纳米环的分布情况;用振动样品磁强计(VSM)测量了NiFe纳米环的磁化曲线,显示出两种磁状态,即涡旋态(Vortex state)和双畴态(Onion state),并利用OOMMF软件对NiFe纳米环的磁化翻转过程进行微磁模拟,观察到纳米环不同磁化状态下的自旋组态。 展开更多
关键词 磁性纳米环 聚苯乙烯微球模板 涡旋态 微磁模拟
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涡旋磁纳米颗粒——崭新的生物医用磁性纳米平台 被引量:4
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作者 吴建鹏 刘晓丽 +3 位作者 张欢 张艺凡 骆艳娥 樊海明 《生物化学与生物物理进展》 SCIE CAS CSCD 北大核心 2015年第7期593-605,共13页
相比于超顺磁性纳米颗粒,具有涡旋磁畴的磁性纳米颗粒,由于独特的磁化闭合分布、较大的粒径尺寸及外加磁场中的磁化翻转特性,使得其兼具弱的颗粒间磁相互作用和更优异的磁学性能,在生物医学领域展现出了更好的应用优势和潜力.本综述结... 相比于超顺磁性纳米颗粒,具有涡旋磁畴的磁性纳米颗粒,由于独特的磁化闭合分布、较大的粒径尺寸及外加磁场中的磁化翻转特性,使得其兼具弱的颗粒间磁相互作用和更优异的磁学性能,在生物医学领域展现出了更好的应用优势和潜力.本综述结合近年来国内外对涡旋磁畴的研究及涡旋磁纳米颗粒在生物医学领域的报道,提出了一类新型的生物医用涡旋磁溶胶体系,并以涡旋磁氧化铁纳米盘和纳米环为例,介绍了涡旋磁纳米颗粒的化学合成,并着重论述了这类具有独特涡旋畴结构的纳米颗粒在磁共振成像、抗肿瘤治疗等生物医学应用上的最新研究进展. 展开更多
关键词 涡旋磁纳米颗粒 磁性纳米盘/ MRI造影剂 抗肿瘤治疗
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坡莫合金纳米环微磁学特性研究
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作者 李应琛 王永鑫 +2 位作者 闫泽 刘磊 丁福康 《凝聚态物理学进展》 2020年第4期59-64,共6页
基于微磁学软件MuMax3,我们研究了外磁场下不同几何形状的磁性纳米环(Ni80Fe20)的磁化翻转过程,除了预期的洋葱态和漩涡磁化状态外,在磁化过程中还观察到其它亚稳态。通过磁矩翻转相图和能量密度关系,分析了不同磁化状态的形成和跃迁,... 基于微磁学软件MuMax3,我们研究了外磁场下不同几何形状的磁性纳米环(Ni80Fe20)的磁化翻转过程,除了预期的洋葱态和漩涡磁化状态外,在磁化过程中还观察到其它亚稳态。通过磁矩翻转相图和能量密度关系,分析了不同磁化状态的形成和跃迁,以及磁矩翻转过程中畴壁的传播和湮灭。我们进一步研究了极化电流驱动Ni80Fe20/Cu/Ni80Fe20磁性隧道结中磁矩翻转的过程,研究发现,纳米环隧道结磁矩翻转的电流密度为3.4 &#215;107 A/cm2,临界电流密度大小为传统隧道结的0.63倍,两者的磁矩翻转时间大致相同,约为1000 ps。 展开更多
关键词 MuMax3 坡莫合金 磁性纳米环 磁性隧道结
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Some Applications of Mossbauer Spectroscopy
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作者 Jozef Sitek Katarina Sedlackova Julius Dekan 《Journal of Physical Science and Application》 2013年第5期295-300,共6页
Mossbauer spectroscopy was established as an analytical method 50 years ago and it is still of current interest in many disciplines as mineralogy, environmental science, archeology and biology. Areas of research where... Mossbauer spectroscopy was established as an analytical method 50 years ago and it is still of current interest in many disciplines as mineralogy, environmental science, archeology and biology. Areas of research where Mossbauer spectroscopy is contributing are metals and alloys, magnetic materials, chemical compounds and oxidation states, nanoparticles and many others. Different types of amorphous and nanocrystalline materials (e.g. finemet, nanoperm and hitperm) can be analyzed under different external influence like neutron irradiation or external magnetic field. Mineralogical samples as potassium white micas in sheared basement cover rocks from the Central Western Carpathians and meteorites can be also effectively investigated using MOssbauer spectroscopy. Phase analysis of meteorites can be helpful in their classification and moreover, particular magnetic and non-magnetic components can be analyzed in details. At present, the Mossbauer spectroscopy is also used to analyze environmental materials like zeolites, volcanic tephra and compounds containing ferrate (Fe6+). 展开更多
关键词 Mossbauer spectroscopy nanocrystalline materials white micas Kosice meteorite ferrate Fe6+.
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Fabrication of GO/magnetic graphitic nanocapsule/TiO_2 assemblies as efficient and recyclable photocatalysts 被引量:1
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作者 Zhenqian Cheng Ding Ding +5 位作者 Xiangkun Nie Yiting Xu Zhiling Song Ting Fu Zhuo Chen Weihong Tan 《Science China Chemistry》 SCIE EI CAS CSCD 2015年第7期1131-1136,共6页
In this work, we fabricate an efficient and stable photocatalyst system which has superior recyclability even under concentrated acidic conditions. The photocatalyst is prepared by assembling magnetic graphitic nanoca... In this work, we fabricate an efficient and stable photocatalyst system which has superior recyclability even under concentrated acidic conditions. The photocatalyst is prepared by assembling magnetic graphitic nanocapsules, titania(Ti O2) and graphene oxide(GO) into a complex system through π-π stacking and electrostatic interactions. Such catalytic complex demonstrates very high stability. Even after dispersal into a concentrated acidic solution for one month, this photocatalyst could still be recycled and maintain its catalytic activity. With methyl orange as the model molecule, the photocatalyst is demonstrated to rapidly decompose the molecules with very high photocatalytic activity under both concentrated acidic and neutral condition. Moreover, this photocatalyst retains approximately 100 wt% of its original photocatalytic activity even after multiple experimental runs, of magnetic recycling. Finally, using different samples from natural water sources and different dyes, this GO/ magnetic graphitic nanocapsule/Ti O2 system also demonstrates its high efficiency and recyclability for practical application. 展开更多
关键词 magnetic graphitic nanocapsule graphene oxide TiO2 photocatalyst RECYCLABILITY
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