Search

Your search keyword '"Wang, Yudi"' showing total 635 results
Start Over Author "Wang, Yudi"
635 results on '"Wang, Yudi"'

6. Observation of Enhanced Dynamic {\Delta}G effect near Ferromagnetic Resonance Frequency

Author

Hu, Wenbin, Wang, Yudi, Huang, Mingxian, Zhang, Huaiwu, and Bai, Feiming

Subjects
Physics - Applied Physics
Abstract

The field-dependence elastic modulus of magnetostrictive films, also called {\Delta}E or {\Delta}G effect, is crucial for ultrasensitive magnetic field sensors based on surface acoustic waves (SAWs). In spite of a lot of successful demonstrations, rare attention was paid to the frequency-dependence of {\Delta}E or {\Delta}G effect. In current work, shear horizontal-type SAW delay lines coated with a thin FeCoSiB layer have been studied at various frequencies upon applying magnetic fields. The change of shear modulus of FeCoSiB has been extracted by measuring the field-dependent phase shift of SAWs. It is found that the {\Delta}G effect is significantly enhanced at high-order harmonic frequencies close to the ferromagnetic resonance frequency, increasing by ~82% compared to that at the first SAW mode (128 MHz). In addition, the smaller the effective damping factor of magnetostrictive layer, the more pronounced {\Delta}G effect can be obtained, which is explained by our proposed dynamic magnetoelastic coupling model.

Published
2023
Full Text
View/download PDF

22. Revealing the intrinsic superconducting gap anisotropy in surface-neutralized BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$

Author

Xin, Ziming, Wang, Yudi, Cai, Cong, Wang, Zhengguo, Chen, Lei, Han, Tingting, and Zhang, Yan

Subjects
Condensed Matter - Superconductivity, Condensed Matter - Strongly Correlated Electrons
Abstract

Alkaline-earth iron arsenide (122) is one of the most studied families of iron-based superconductors, especially for angle-resolved photoemission spectroscopy. While extensive photoemission results have been obtained, the surface complexity of 122 caused by its charge-non-neutral surface is rarely considered. Here, we show that the surface of 122 can be neutralized by potassium deposition. In potassium-coated BaFe$_2$(As$_{0.7}$P$_{0.3}$)$_2$, the surface-induced spectral broadening is strongly suppressed, and hence the coherent spectra that reflect the intrinsic bulk electronic state recover. This enables the measuring of superconducting gap with unpreceded precision. The result shows the existence of two pairing channels. While the gap anisotropy on the outer hole/electron pockets can be well fitted using an s$_\pm$ gap function, the gap anisotropy on the inner hole/electron shows a clear deviation. Our results provide quantitative constraints for refining theoretical models and also demonstrate an experimental method for revealing the intrinsic electronic properties of 122 in future studies., Comment: 14 pages, 4 figures with Supplementary Information

Published
2021
Full Text
View/download PDF

26. Intermixing of iron and cobalt with oxygen-rich magnesium oxide in CoFeB/MgO/CoFeB magnetic tunneling junctions.

Author

Gribelyuk, Michael A., Kalitsov, Alan, Jung, Wonjoon, Wang, Yudi, Tran, Michael, Xu, Xiaoyu, and Santos, Tiffany

Subjects
MAGNETIC tunnelling, ELECTRON energy loss spectroscopy, IRON, SPECTROSCOPIC imaging, PERPENDICULAR magnetic anisotropy, MAGNESIUM oxide, TUNNEL magnetoresistance
Abstract

Atomic-scale spectroscopic imaging of sputtered magnetic tunnel junction structures with a thick oxygen-rich MgO barrier reveals the diffusion of iron and cobalt into the MgO barrier from CoFeB electrodes. First principles calculations are performed to (1) confirm that Fe diffusion through Mg vacancies is energetically favorable, (2) quantify the reduction of interfacial perpendicular magnetic anisotropy due to Fe diffusion into MgO, and (3) predict that the presence of Fe impurities in MgO causes an increased leakage and a tunneling magnetoresistance decrease. Through the chemical shift of the Fe L3 edge and the peak ratio Fe L3/Fe L2 measured by electron energy loss spectroscopy, we suggest that, within MgO, iron with mixed oxidation state Fe2+ and Fe3+ or higher is found in the as-grown structure, which is reduced by annealing to Fe2+. These results indicate that the stoichiometry of as-deposited MgO barrier layers plays an important role in controlling the microstructure and optimizing the performance of magnetic tunnel junctions. [ABSTRACT FROM AUTHOR]

Published
2024
Full Text
View/download PDF

41. Research on Prevention of Affective Nihilism in Existential Depression: an Existential Approach in Educational Settings

Author

Wang, Yudi, Striełkowski, Wadim, Editor-in-Chief, Black, Jessica M., Series Editor, Butterfield, Stephen A., Series Editor, Chang, Chi-Cheng, Series Editor, Cheng, Jiuqing, Series Editor, Dumanig, Francisco Perlas, Series Editor, Al-Mabuk, Radhi, Series Editor, Scheper-Hughes, Nancy, Series Editor, Urban, Mathias, Series Editor, Webb, Stephen, Series Editor, Holl, Augustin, editor, Chen, Jun, editor, and Guan, Guiyun, editor

Published
2022
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results