Electronic and Magnetic Structure of LaSr-2×4 Manganese Oxide Molecular Sieve Nanowires

2014 ◽  
Vol 20 (3) ◽  
pp. 760-766 ◽  
Author(s):  
Jaume Gazquez ◽  
Adrián Carretero-Genevrier ◽  
Martí Gich ◽  
Narcís Mestres ◽  
María Varela
Keyword(s):  
Manganese Oxide ◽  
Magnetic Structure ◽  
Molecular Sieve ◽  
Magnetic Circular Dichroism ◽  
Mixed Valence ◽  
Double Exchange ◽  
Crystallographic Structure ◽  
Spin Orbital ◽  
Electronic And Magnetic Structure ◽  
Scanning Transmission

AbstractIn this study we combine scanning transmission electron microscopy, electron energy loss spectroscopy and electron magnetic circular dichroism to get new insights into the electronic and magnetic structure of LaSr-2×4 manganese oxide molecular sieve nanowires integrated on a silicon substrate. These nanowires exhibit ferromagnetism with strongly enhanced Curie temperature (Tc>500 K), and we show that the new crystallographic structure of these LaSr-2×4 nanowires involves spin orbital coupling and a mixed-valence Mn3+/Mn4+, which is a must for ferromagnetic ordering to appear, in line with the standard double exchange explanation.

scholarly journals Quantitative determination of site-specific magnetic structure in TEM

2014 ◽  
Vol 70 (a1) ◽  
pp. C1451-C1451
Author(s):  
jing Zhu ◽  
Ziqiang Wang ◽  
Xiaoyan Zhong ◽  
Rong Yu ◽  
Dongsheng Song ◽  
...  
Keyword(s):  
Circular Dichroism ◽  
Magnetic Structure ◽  
Magnetic Circular Dichroism ◽  
Magnetic Moments ◽  
Nanometer Scale ◽  
Crystallographic Site ◽  
Spin Orbital ◽  
Site Specific ◽  
Nano Scale ◽  
Circular Dichroïsm

Determining the magnetic structure of material on a nanometer scale is fundamental for understanding its nano-scale magnetic property and developing nano-scale magnetic devices. Site-specific electron energy-loss magnetic chiral dichroism (site-specific EMCD[1],[2]) method is come up with to get the crystallographic site-specific magnetic information of nanostructures. By constructively using the dynamical diffraction conditions in EMCD experiments, we experimentally achieve the crystallographic site-specific magnetic structure of a nanostructure of NiFe2O4 as an example in transmission electron microscope, with its site-specific magnetic circular dichroism spectra, and its site-specific spin/orbital magnetic moments extracted. The site-specific EMCD method shows its unique capability for solving the crystallographic site-specific magnetic structure on nano-scale, compared with X-ray magnetic circular dichroism and neutron diffraction. This work may benefit the research and application of magnetic materials on a nanometer scale. Acknowledgement: This work is financially supported by National 973 Project of China (2009CB623701) and Chinese National Nature Science Foundation (11374174,51390471 ). This work made use of the resources of the Beijing National Center for Electron Microscopy.

Heisenberg and double exchange in iron mixed valence [Fe6S6]+ supercluster

1997 ◽  
Vol 90 (3) ◽  
pp. 445-463 ◽  
Author(s):  
M. CZERWINSKI ◽  
J. DĄBROWSKI
Keyword(s):  
Mixed Valence ◽  
Double Exchange

Peroxymonosulfate activation and pollutants degradation over highly dispersed CuO in manganese oxide octahedral molecular sieve

2017 ◽  
Vol 422 ◽  
pp. 754-762 ◽  
Author(s):  
Jun Li ◽  
Peng Ye ◽  
Jia Fang ◽  
Manye Wang ◽  
Deming Wu ◽  
...  
Keyword(s):  
Manganese Oxide ◽  
Molecular Sieve ◽  
Highly Dispersed

High‐nuclearity mixed‐valence magnetic clusters: A general solution of the double exchange problem

1996 ◽  
Vol 105 (16) ◽  
pp. 6892-6909 ◽  
Author(s):  
J. J. Borrás‐Almenar ◽  
J. M. Clemente ◽  
E. Coronado ◽  
A. V. Palii ◽  
B. S. Tsukerblat ◽  
...  
Keyword(s):  
General Solution ◽  
Mixed Valence ◽  
Double Exchange ◽  
Magnetic Clusters
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