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利用高分辨电子显微学方法(HREM)研究了纳米氧化层镜面反射自旋阀多层结构Ta(35nm)Ni80Fe20(2nm)Ir17Mn83(6nm)Co90Fe10(15nm)NOL1Co90Fe10(2nm)Cu(22nm)Co90Fe10(15nm)NOL2Ta(3nm).该自旋阀的巨磁电阻(GMR)效应高达15%,较无此镜面反射纳米氧化层(NOL)的自旋阀提高近1倍,同时交换偏置场亦有所增强.高分辨显微结构分析表明,介于钉扎层与被钉扎层之间的氧化层(NOL1)并未完全氧化,即除氧化过程生成的CoFe氧化物
关键词:
自旋阀
纳米氧化层
高分辨电子显微学
巨磁电阻效应 相似文献
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Bipolar resistive switching is studied in BiFe0.95Zn0.05O3 films prepared by pulsed laser deposition on (001) SrTiO3 substrate, with LaNiO3 as the bottom electrode, and Pt as the top electrode. Multiple steps of resistance change are ob- served in the resistive switching process with a slow voltage sweep, indicating the formation/rupture of multiple conductive filaments. A resistive ratio of the high resistance state (HRS) to the low resistance state (LRS) of over three orders of mag- nitude is observed. Furthermore, the conduction mechanism is confirmed to be space-charge-limited conduction with the Schottky emission at the interface with the top Pt electrodes in the HRS, and Ohmic in the LRS. Impedance spectroscopy demonstrates a conductive ferroelectric/interfacial dielectric 2-layer structure, and the formation/rupture of the conductive filaments mainly occurs at the interfacial dielectric layer close to the top Pt electrodes. 相似文献
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Zn0.98 Cu0.02 O powders are prepared by the sol-gel method.A small number of CuO impurity phases are observed by the x-ray diffraction,indicating the solubility of Cu in ZnO is less than 2 at.%.The Zn0.98 Cu0.02 O powders exhibit diamagnetism at 300 K and paramagnetism at 5 K.After subtracting the diamagnetic contribution of ZnO bulk and the paramagnetic contribution of defects,Cu ions exhibit weak paramagnetism.By codoping Cu with Co or Mn in ZnO,only paramagnetism is observed at room temperature. 相似文献
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报道了一种新型Ag/Ag3PO4/g-C3N4三元复合光催化剂的制备及其半导体界面处的快速载流子分离所引起的光催化活性的显著增强效应。通过X射线衍射,扫描电子显微镜,紫外-可见吸收光谱以及光致发光光谱等就其晶体结构、形貌、组分、光学吸收以及载流子的快速分离行为进行了表征与分析。以罗丹明B作为模型化合物分子,研究发现,所制备的Ag/Ag3PO4/g-C3N4三元复合光催化剂在可见光照射下表现出比Ag3PO4以及Ag3PO4/g-C3N4二元催化剂更为优异的光催化活性。研究认为,Ag3PO4表面尺寸约为40 nm的Ag纳米粒子在可见光下受激所产生的等离子表面共振效应以及Ag3PO4与g-C3N4界面处所形成的类似异质结结构对所制备的Ag/Ag3PO4/g-C3N4三元复合光催化剂光催化活性的显著增强起到重要作用。 相似文献
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Dependence of Tunnel Resistance on the Injection Current of Magnetic Tunnel Junctions 总被引:3,自引:0,他引:3 下载免费PDF全文
Anomalous transport behaviour,i.e.the dependence of the tunnel resistance on the injection current,has been discovered in Ta/Co/Al2O3/FeNi tunnel junctions.The zero-field voltage-current characteristic of the magnetic tunnelling junction obeys the transport principle of the normal tunnel junction at low injection current,but it exhibits a negative resistance behaviour when the injection current is raised to the break-over current level.The physics of the restorable electric breakdown has been initially studied. 相似文献
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Magnetic-Field-Induced Semimetal-Insulator-like Transition in Highly Oriented Pyrolitic Graphite 下载免费PDF全文
We report the extraordinarily large positive magnetoresistances (MR, 69400% at 4.5K under a magnetic field of 8.15 T), de Hass-van Alphen oscillations effect at 10 K and the semimetal-Jnsulator-like transition in a wide range of temperature in highly oriented pyrolitic graphite (HOPG). Besides a dominating ordinary MR (OMR) mechanism in the free-electron mode, it is realized from qualitative analysis that the Coulomb interacting quasiparticles within graphite layers play some roles. However it is difficult to associate the transition with the simple OMR theory. In order to investigate the possible origins of the transition, further analysis is carried out. It is revealed that the magnetic-field-induced behaviour is responsible for the semimetal-insulator-like transitions in HOPG. 相似文献
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对用离子束溅射制备的Ni0.8Co0.2-SiO2颗粒膜的Hall效应进行了研究.当Ni0.8Co0.2合金的含量为43vol%时,在9.5×105A/m的外磁场下,样品的室温Hall电阻率达6.3μΩ·cm ,高于普通磁性金属两个数量级以上,还研究了不同NiCo组分样品的电阻率与温度的关系(95—300K),发现x<xc(逾渗组分)时,电阻率与-logT成正比,电阻温度系数为负;当x<xc时,逐渐呈现金属性;而当x≈xc时,为过渡态.还用透射电子显微镜和振动样品磁强计等手段对样品的微结构和磁性进行了对比研究,表明金属-绝缘体颗粒膜中在逾渗阈值附近有较大的Hall效应,这与样品的微结构有密切关系.
关键词: 相似文献
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