Showing 1–4 of 4 results for author: Zhu, M H

Macro deformation twins in single-crystal aluminum

Authors: F. Zhao, L. Wang, D. Fan, B. X. Bie, X. M. Zhou, T. Suo, Y. L. Li, M. W. Chen, C. Liu, M. L. Qi, M. H. Zhu, S. N. Luo

Abstract: Deformation twinning in pure aluminum has been considered to be a unique property of nanostructured aluminum. A lingering mystery is whether deformation twinning occurs in coarse-grained or single-crystal aluminum, at scales beyond nanotwins. Here, we present the first experimental demonstration of macro deformation twins in single-crystal aluminum formed under ultrahigh strain-rate ($\sim$10$^6$… ▽ More Deformation twinning in pure aluminum has been considered to be a unique property of nanostructured aluminum. A lingering mystery is whether deformation twinning occurs in coarse-grained or single-crystal aluminum, at scales beyond nanotwins. Here, we present the first experimental demonstration of macro deformation twins in single-crystal aluminum formed under ultrahigh strain-rate ($\sim$10$^6$ s$^{-1}$), large shear strain (200$\%$) via dynamic equal channel angular pressing. Deformation twinning is rooted in the rate dependences of dislocation motion and twinning, which are coupled, complementary processes during severe plastic deformation under ultrahigh strain rates. △ Less

Submitted 15 October, 2015; originally announced October 2015.

Comments: 4 pages and 4 figures

Journal ref: Phys. Rev. Lett. 116, 075501 (2016)

Universal behavior of giant electroresistance in epitaxial La0.67Ca0.33MnO3 thin films

Authors: Y. G. Zhao, Y. H. Wang, G. M. Zhang, B. Zhang, X. P. Zhang, C. X. Yang, P. L. Lang, M. H. Zhu, P. C. Guan

Abstract: We report a giant resistance drop induced by dc electrical currents in La0.67Ca0.33MnO3 epitaxial thin films. Resistance of the patterned thin films decreases exponentially with increasing current and a maximum drop shows at the temperature of resistance peak Tp. Variation of resistance with current densities can be scaled below and above Tp, respectively. This work can be useful for the future… ▽ More We report a giant resistance drop induced by dc electrical currents in La0.67Ca0.33MnO3 epitaxial thin films. Resistance of the patterned thin films decreases exponentially with increasing current and a maximum drop shows at the temperature of resistance peak Tp. Variation of resistance with current densities can be scaled below and above Tp, respectively. This work can be useful for the future applications of electroresistance. △ Less

Submitted 22 March, 2005; v1 submitted 28 July, 2004; originally announced July 2004.

Comments: 13 pages, 4 figures

Journal ref: Appl. Phys. Lett. 86, 122502 (2005)

Influence of the starting composition on the structural and superconducting properties of MgB2 phase

Authors: Y. G. Zhao, X. P. Zhang, P. T. Qiao, H. T. Zhang, S. L. Jia, B. S. Cao M. H. Zhu, Z. H. Han, X. L. Wang, B. L. Gu

Abstract: We report the preparation of Mg$_{1-x}$B$_{2}$ (0$\le$x$\le$0.5) compounds with the nominal compositions. Single phase MgB$_{2}$ was obtained for x=0 sample. For 0$<$x$\le$0.5, MgB$_{4}$ coexists with "MgB$_{2}$" and the amount of MgB$_{4}$ increases with x. With the increase of x, the lattice parameter ${\it c}$ of "MgB$_{2}$" increases and the lattice parameter ${\it a}$ decreases, correspondi… ▽ More We report the preparation of Mg$_{1-x}$B$_{2}$ (0$\le$x$\le$0.5) compounds with the nominal compositions. Single phase MgB$_{2}$ was obtained for x=0 sample. For 0$<$x$\le$0.5, MgB$_{4}$ coexists with "MgB$_{2}$" and the amount of MgB$_{4}$ increases with x. With the increase of x, the lattice parameter ${\it c}$ of "MgB$_{2}$" increases and the lattice parameter ${\it a}$ decreases, correspondingly T$_{c}$ of Mg$_{1-x}$B$_{2}$ decreases. The results were discussed in terms of the presence of Mg vacancies or B interstitials in the MgB$_{2}$ structure. This work is helpful to the understanding of the MgB$_{2}$ films with different T$_{c}$, as well as the Mg site doping effect for MgB$_{2}$. △ Less

Submitted 3 May, 2001; originally announced May 2001.

Comments: 11 pages, 4 figures

Effect of Li doping on structure and superconducting transition temperature of Mg1-xLixB2

Authors: Y. G. Zhao, X. P. Zhang, P. T. Qiao, H. T. Zhang, S. L. Jia, B. S. Cao M. H. Zhu, Z. H. Han, X. L. Wang, B. L. Gu

Abstract: We report the preparation of Mg1-xLixB2 compounds. Nearly single phased samples were obtained for x<0.3. The in-plane lattice parameter a decreases with Li doping, while the lattice parameter c does not show obvious change. The superconducting transition temperature of Mg1-xLixB2 decreases with Li doping and loss of superconductivity occurs for x=0.5 sample. The results of our work are consisten… ▽ More We report the preparation of Mg1-xLixB2 compounds. Nearly single phased samples were obtained for x<0.3. The in-plane lattice parameter a decreases with Li doping, while the lattice parameter c does not show obvious change. The superconducting transition temperature of Mg1-xLixB2 decreases with Li doping and loss of superconductivity occurs for x=0.5 sample. The results of our work are consistent with the prediction of the hole superconductivity mechanism. △ Less

Submitted 2 March, 2001; originally announced March 2001.

Comments: 5 pages, 4 figures