Observations of Superlattice Reflections Associated with Charge Ordering in Bi0.2Ca0.8MnO3 with an Energy-Filter

1998 ◽  
Vol 4 (S2) ◽  
pp. 574-575
Author(s):  
Y. Murakami ◽  
D. Shindo ◽  
K. Hiraga ◽  
T. Oikawa ◽  
M. Kersker
Keyword(s):  
Magnetic Properties ◽  
Critical Temperature ◽  
Electron Diffraction ◽  
Diffuse Scattering ◽  
Lattice Strain ◽  
Diffraction Method ◽  
Charge Ordering ◽  
Ion Milling ◽  
Interesting Phenomenon ◽  
Small Charge

A perovskite manganese oxide of Bi0.2Ca0.8MnO3 exhibits charge ordering of Mn3+ and Mn4+ ions upon cooling. This is an interesting phenomenon from both academic and practical viewpoints, since the charge ordering is accompanied by significant changes in both electric and magnetic properties of the oxide. Since a difference of scattering amplitudes between Mn3+ and Mn4+ is quite small, charge ordering can be observable as superlattice reflections due to the lattice strain caused by this ordering with an electron diffraction method. However, the background in an electron diffraction pattern, which is mainly caused by plasmon scattering, has hindered a precise investigation of the weak diffuse scattering. The purpose of the present work is to assess an efficiency of an omega-type energy-filter in detailed observations of the weak superlattice reflections associated with the charge ordering.Specimens of Bi0.2Ca0.8MnO3 were prepared by a conventional ion-milling technique. The critical temperature of charge ordering (TCo) was determined to be 160K by resistivity and magnetization measurements.

Stress-Induced Ordering in Y203-Stabilized Tetragonal Zr02

1985 ◽  
Vol 43 ◽  
pp. 222-223
Author(s):  
J. Y. Koo ◽  
M. P. Anderson
Keyword(s):  
Electron Diffraction ◽  
Ionic Conduction ◽  
Electron Diffraction Study ◽  
Ceramic Materials ◽  
Bright Field Image ◽  
Transformation Toughening ◽  
Ion Milling ◽  
Thin Foils ◽  
Carbon Coated ◽  
Convergent Beam

Tetragonal Zr02 has been used as a toughening phase in a large number of ceramic materials. In this system, complex diffraction phenomena have been observed and an understanding of the origin of the diffraction effects provides important information on the nature of transformation toughening, ionic conduction, and phase destabilization. This paper describes the results of an electron diffraction study of Y203-stabilized, tetragonal Zr02 polycrystals (Y-TZP).Thin foils from the bulk Y-TZP sample were prepared by careful grinding and cryo ion-milling. They were carbon coated and examined in a Philips 400T/FEG microscope. Fig. 1 shows a typical bright field image of the 100% tetragonal(t) Zr02. The tetragonal structure was identified by both bulk x-ray diffraction and convergent beam electron diffraction (Fig. 2. A local region within a t-Zr02 grain was subjected to an intense electron beam irradiation which caused partial martensitic transformation of the t-Zr02 to monoclinic(m) symmetry, Fig. 3 A.

scholarly journals High-yield fabrication of perpendicularly magnetised synthetic antiferromagnetic nanodiscs

Nano Research ◽  
2021 ◽  
Author(s):  
Emma N. Welbourne ◽  
Tarun Vemulkar ◽  
Russell P. Cowburn
Keyword(s):  
Thin Film ◽  
Magnetic Properties ◽  
Sacrificial Layer ◽  
Nanosphere Lithography ◽  
High Yield ◽  
Perpendicular Anisotropy ◽  
Ion Milling ◽  
Lift Off

AbstractSynthetic antiferromagnetic (SAF) particles with perpendicular anisotropy display a number of desirable characteristics for applications in biological and other fluid environments. We present an efficient and effective method for the patterning of ultrathin Ruderman-Kittel-Kasuya-Yoshida coupled, perpendicularly magnetised SAFs using a combination of nanosphere lithography and ion milling. A Ge sacrificial layer is utilised, which provides a clean and simple lift-off process, as well as maintaining the key magnetic properties that are beneficial to target applications. We demonstrate that the method is capable of producing a particularly high yield of well-defined, thin film based nanoparticles.

Charge ordering and magnetic properties of LaxSm0.5-xCa0.5MnO3 manganite

2021 ◽  
Author(s):  
Yan Wang ◽  
Hui Zhang ◽  
Haiou Wang ◽  
Dexin Yang ◽  
Shuai Huang ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Charge Ordering

scholarly journals The Structure and Magnetic Properties of Rapidly Quenched Fe72Ni8Nb4Si2B14 Alloy

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 5
Author(s):  
Lukasz Hawelek ◽  
Tymon Warski ◽  
Patryk Wlodarczyk ◽  
Marcin Polak ◽  
Przemyslaw Zackiewicz ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Relaxation Process ◽  
Glassy State ◽  
Diffraction Method ◽  
Soft Magnetic Materials ◽  
Process Time ◽  
Complex Permeability ◽  
Soft Magnetic ◽  
Conventional Heat Treatment ◽  
Glass Relaxation

The complex structural and magnetic studies of the annealed rapidly quenched Cu-free Fe72Ni8Nb4Si2B14 alloy (metallic ribbons form) are reported here. Based on the calorimetric results, the conventional heat treatment process (with heating rate 10 °C/min and subsequent isothermal annealing for 20 min) for wound toroidal cores has been optimized to obtain the least lossy magnetic properties (for the minimum value of coercivity and magnetic core losses at 50 Hz). For optimal conditions, the complex permeability in the 104–108 Hz frequency range together with core power losses obtained from magnetic induction dependence up to the frequency of 400 kHz was successfully measured. The average and local crystal structure was investigated by the use of the X-ray diffraction method and the transmission electron microscopy observations and proved its fully glassy state. Additionally, for the three temperature values, i.e., 310, 340 and 370 °C, the glass relaxation process study in the function of annealing time was carried out to obtain a deeper insight into the soft magnetic properties: magnetic permeability and cut-off frequency. For this type of Cu-free soft magnetic materials, the control of glass relaxation process (time and temperature) is extremely important to obtain proper magnetic properties.

Three-phase structure invariants and structure factors determined with the quantitative convergent-beam electron diffraction method

1999 ◽  
Vol 55 (2) ◽  
pp. 188-196 ◽  
Author(s):  
R. Høier ◽  
C. R. Birkeland ◽  
R. Holmestad ◽  
K Marthinsen
Keyword(s):  
Electron Diffraction ◽  
Phase Structure ◽  
Diffraction Method ◽  
Convergent Beam Electron Diffraction ◽  
Beam Electron ◽  
Structure Factors ◽  
Refinement Method ◽  
Three Phase ◽  
Phase Sensitive ◽  
Convergent Beam

Quantitative convergent-beam electron diffraction is used to determine structure factors and three-phase structure invariants. The refinements are based on centre-disc intensities only. An algorithm for parameter-sensitive pixel sampling of experimental intensities is implemented in the refinement procedure to increase sensitivity and computer speed. Typical three-beam effects are illustrated for the centrosymmetric case. The modified refinement method is applied to determine amplitudes and three-phase structure invariants in noncentrosymmetric InP. The accuracy of the results is shown to depend on the choice of the initial parameters in the refinement. Even unrealistic starting assumptions and incorrect temperature factor lead to stable results for the structure invariant. The examples show that the accuracy varies from 1 to 10° in the electron three-phase invariants determined and from 0.5 to 5% for the amplitudes. Individual phases could not be determined in the present case owing to spatial intensity correlations between phase-sensitive pixels. However, for the three-phase structure invariant, stable solutions were found.

Synthesis, Structure and Magnetic Properties of Monoclinic Nb12O29

2000 ◽  
Vol 658 ◽  
Author(s):  
J. E. L. Waldron ◽  
M. A. Green
Keyword(s):  
Magnetic Properties ◽  
Magnetic Order ◽  
Bulk Sample ◽  
Charge Ordering ◽  
Rapid Reduction ◽  
One Dimensional ◽  
Range Magnetic Order ◽  
A Charge ◽  
Ordering Transition ◽  
Long Range Magnetic Order

ABSTRACTThe synthesis, structure and magnetic properties of monoclinic Nb12O29 are described. The synthesis of a pure bulk sample is difficult due to the large number of other similar phases. It is achieved by rapid reduction of H-Nb2O5 with Nb metal. The compound is shown to undergo a charge ordering transition at low temperature which provokes long range magnetic order in an intriguing one dimensional arrangement.

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