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91.
Disorder-induced noncollinear ferromagnetism is a common feature of kinetic-exchange models for ferromagnetic (III,Mn)V semiconductors with randomly distributed Mn ions. The instability of the collinear state is due to long-ranged fluctuations involving a large fraction of the localized magnetic moments. In cases were the true ground state magnetization is reduced substantially from the maximum value of the collinear state one finds a complex energy landsacpe with many metastable minima. Finally we report on studies of the influence of an external field realigning the Mn spins starting from a glassy zero-field ground state. 相似文献
92.
O. Fedorych Z. Wilamowski M. Potemski M. Byszewski J. Sadowski 《Journal of Superconductivity》2003,16(1):51-53
MBE grown Ga1–x
Mn
x
As layers were investigated by means of magnetic resonance techniques. Two phases can be distinguished: an almost isotropic ferromagnetic phase in insulating layers and an anisotropic ferromagnetic phase in the metallic Ga1–x
Mn
x
As. Under a strong magnetic field the field-induced insulator-to-metal transition is accompanied by the change from the ferromagnetic to the ferrimagnetic phase. 相似文献
93.
用MS—Xα方法研究了Co1-xMnx合金(bcc结构)的电子结构与磁性,计算结果表明:原子之间存在负交换耦合,且随着Mn含量的增加,负交换耦合增强,从而导致bcc结构的Co1-xMnx合金的铁磁性减弱,计算结果与实验符合得较好。 相似文献
94.
D. Chiba M. Yamanouchi F. Matsukura E. Abe Y. Ohno K. Ohtani H. Ohno 《Journal of Superconductivity》2003,16(1):179-182
We have investigated the magnetotransport properties of field-effect transistors (FET) having a III–V ferromagnetic semiconductor channel layer. One can control not only the ferromagnetic transition temperature T
C but also the magnetization and the coercive force of (In,Mn)As channel layers isothermally and reversibly by gate electric fields. A small change of the magnetization upon application of gate electric fields is also observed in FETs with a (Ga,Mn)As channel. Results on a (Al,Ga,Mn)As channel FET are also presented. 相似文献
95.
Ferromagnetic,Folded Electrode Composite as a Soft Interface to the Skin for Long‐Term Electrophysiological Recording
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Kyung‐In Jang Han Na Jung Jung Woo Lee Sheng Xu Yu Hao Liu Yinji Ma Jae‐Woong Jeong Young Min Song Jeonghyun Kim Bong Hoon Kim Anthony Banks Jean Won Kwak Yiyuan Yang Dawei Shi Zijun Wei Xue Feng Ungyu Paik Yonggang Huang Roozbeh Ghaffari John A. Rogers 《Advanced functional materials》2016,26(40):7281-7290
A class of ferromagnetic, folded, soft composite material for skin‐interfaced electrodes with releasable interfaces to stretchable, wireless electronic measurement systems is introduced. These electrodes establish intimate, adhesive contacts to the skin, in dimensionally stable formats compatible with multiple days of continuous operation, with several key advantages over conventional hydrogel‐based alternatives. The reported studies focus on aspects ranging from ferromagnetic and mechanical behavior of the materials systems, to electrical properties associated with their skin interface, to system‐level integration for advanced electrophysiological monitoring applications. The work combines experimental measurement and theoretical modeling to establish the key design considerations. These concepts have potential uses across a diverse set of skin‐integrated electronic technologies. 相似文献
96.
Jae-Hyeon Cho Yu Jin Kim Su Hwan Kim Young-Jin Lee Jun-Yong Choi Geon-Tae Hwang Jungho Ryu Sang Kyu Kwak Wook Jo 《Journal of the American Ceramic Society》2022,105(4):2655-2662
A nickel–zinc ferrite system, which is one of the well-known versatile soft-ferromagnetic oxides, was investigated in terms of magnetoelectric (ME) coupling at room temperature. Herein, we demonstrated that spin canting is manipulated through a composition-induced structural transition from an inverse to a normal spinel structure, leading to modulation in the ME coupling. The ME coefficient was maximized at 60 at.% Zn substitution with a value of 0.1 mV/(Oe·cm), denoting ∼70% enhancement compared to that of the pure nickel ferrite. It was revealed that the interspin angle is enhanced along the octahedral site at up to ∼60 at.% Zn substitution, consistent with the composition level at the culmination of the ME coupling, evidenced by X-ray diffraction profiles and magnetic hysteresis loops combined with density functional theory calculations. Given that this approach is based on a tractable fabrication method, this study is expected to be widely used in modulation of the ME coupling in spinel-structured oxides. 相似文献
97.
采用溶胶-凝胶(sol-gel)法制备La0.67Sr0.33-xAgx-y□yMnO3/Agy(x=0.20,0.30)多晶粉末,经压制与1 400℃/12h烧结获得相应的块体材料,借助X射线衍射仪(XRD)、扫描电镜(SEM)、透射电镜(TEM)和多功能物性测量系统(PPMS,附件VSM),对材料的相结构、微观结构和磁性能进行研究。结果表明:La0.67Sr0.33-xAgx-y□yMnO3/Agy粉末形貌为接近球形的凸多面体,平均粒度在150 nm左右,块体材料结构致密但粒度变大。另外,粉末与块体材料中都有金属Ag相和Sr空位存在。在室温下块体材料的磁电阻较小,而且为负值。在低温区,外加磁场越高,则磁电阻越大,在外加磁场为3T、温度为174和20 K条件下,La0.67Sr0.13Ag0.20-y□yMnO3/Agy的磁电阻分别为-37.5%和-43.3%,在141和20 K温度下La0.67Sr0.03Ag0.30-y□yMnO3/Agy的磁电阻分别为-45.1%和-53.9%。 相似文献
98.
采用离子能量为 100keV,剂量为 3× 1016cm- 2的离子注入技术,室温下往 n型 Ge( 111)单晶 衬底注入 Mn+离子,注入后的样品进行 400℃热处理.利用 X-射线衍射法 (XRD)和原子力显微 镜( AFM)对注入后的样品进行了结构和形貌分析, 俄歇电子能谱法 (AES)进行了组分分析,交变 梯度样品磁强计( AGM)进行了室温磁性测量.结果表明原位注入样品的结构是非晶的,热处理后 发生晶化现象.没有在样品中观察到新相形成. Mn离子较深的注入进 Ge衬底,在 120 nm处 Mn原子百分比浓度达到最高为 8%.热处理后的样品表现出了室温铁磁特性. 相似文献
99.
100.
利用流变相反应法制备得到Zn1-xCoxO(x=0.02、0.04、0.06、0.08)稀磁半导体材料。X射线衍射分析,发现Co的掺杂并未改变ZnO的纤锌矿结构,并没有杂质相的生成,衍射峰的峰位随着Co掺杂向高角度移动,Co已进入ZnO晶格。电镜及吸收光谱进一步表明样品中没有第二相的出现,Co2+成功掺入ZnO晶格。采用超导量子干涉磁强仪测量Zn0.96Co0.04O的磁性,样品在300K存在明显的磁饱和现象和磁滞回线,表明具有室温下铁磁性,其磁性来源可以用束缚磁极化子(BMPs)模型解释。 相似文献