scholarly journals Synthesis and ESR Study of Transition from Ferromagnetism to Superparamagnetism in La0.8Sr0.2MnO3 Nanomanganite

2020 ◽  
Author(s):  
Mondher Yahya ◽  
Faouzi Hosni ◽  
Ahmed Hichem Hamzaoui
Keyword(s):  
Crystallite Size ◽  
Magnetic State ◽  
Resonance Field ◽  
Magnetic Domain ◽  
Single Domain ◽  
State Transitions ◽  
G Factor ◽  
Domain Structures ◽  
Crystallite Sizes ◽  
Superparamagnetic State

Electron spin resonance (ESR) spectroscopy was used to determine the magnetic state transitions of nanocrystalline La0.8Sr0.2MnO3 at room temperature, as a function of crystallite size. Ferromagnetic nanoparticles having an average crystallite size ranging from 9 to 57 nm are prepared by adopting the autocombustion method with two-step synthesis process. Significant changes of the ESR spectra parameters, such as the line shape, resonance field (Hr), g-factor, linewidth (∆Hpp), and the low-field microwave absorption (LFMA) signal, are indicative of the change in magnetic domain structures from superparamagnetism to single-domain and multi-domain ferromagnetism by increase in the crystallite size. Samples with crystallite sizes less than 24.5 nm are in a superparamagnetic state. Between 24.5 and 32 nm, they are formed by a single-domain ferromagnetic. The multi-domain state arises for higher sizes. In superparamagnetic region, the value of g-factor is practically constant suggesting that the magnetic core size is invariant with decreasing crystallite size. This contradictory observation with the core-shell model was explained by the phenomenon of phase separation that leads to the formation of a new magnetic state that we called multicore superparamagnetic state.

Resistance of single domain walls in half-metallic CrO2 epitaxial nanostructures

Nanoscale ◽  
2021 ◽  
Author(s):  
Lijuan Qian ◽  
Shiyu Zhou ◽  
Kang Wang ◽  
Gang Xiao
Keyword(s):  
Electron Transport ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Single Domain ◽  
Half Metallic ◽  
Domain Structures ◽  
Active Electron ◽  
Excess Resistance

Magnetic domain structures are active electron transport agents and can be used to induce large magnetoresistance (MR), particularly in half-metallic solids. We have studied the excess resistance induced by a...

Temperature Dependence of Magnetic Domains and Wall Structures

1972 ◽  
Vol 30 ◽  
pp. 496-497
Author(s):  
Sonoko Tsukahara ◽  
Tadami Taoka ◽  
Hisao Nishizawa
Keyword(s):  
Temperature Dependence ◽  
Domain Walls ◽  
Magnetic Domain ◽  
Iron Film ◽  
Objective Lens ◽  
Lorentz Microscopy ◽  
Domain Structures ◽  
Wall Structures ◽  
Crystal Films ◽  
Metallurgical Structure

The high voltage Lorentz microscopy was successfully used to observe changes with temperature; of domain structures and metallurgical structures in an iron film set on the hot stage combined with a goniometer. The microscope used was the JEM-1000 EM which was operated with the objective lens current cut off to eliminate the magnetic field in the specimen position. Single crystal films with an (001) plane were prepared by the epitaxial growth of evaporated iron on a cleaved (001) plane of a rocksalt substrate. They had a uniform thickness from 1000 to 7000 Å.The figure shows the temperature dependence of magnetic domain structure with its corresponding deflection pattern and metallurgical structure observed in a 4500 Å iron film. In general, with increase of temperature, the straight domain walls decrease in their width (at 400°C), curve in an iregular shape (600°C) and then vanish (790°C). The ripple structures with cross-tie walls are observed below the Curie temperature.

Highlights in the history of X-ray topography1

1995 ◽  
Vol 210 (6) ◽  
Author(s):  
A. R. Lang
Keyword(s):  
Magnetic Domain ◽  
Diffraction Theory ◽  
Dislocation Loops ◽  
X Ray Diffraction ◽  
X Ray ◽  
Domain Structures ◽  
Structure Factors ◽  
History Of ◽  
Dislocation Sources ◽  
Non Destructive

AbstractX-ray topography provides a non-destructive method of mapping point-by-point variations in orientation and reflecting power within crystals. The discovery, made by several workers independently, that in nearly perfect crystals it was possible to detect individual dislocations by X-ray diffraction contrast started an epoch of rapid exploitation of X-ray topography as a new, general method for assessing crystal perfection. Another discovery, that of X-ray Pendellösung, led to important theoretical developments in X-ray diffraction theory and to a new and precise method for measuring structure factors on an absolute scale. Other highlights picked out for mention are studies of Frank-Read dislocation sources, the discovery of long dislocation helices and lines of coaxial dislocation loops in aluminium, of internal magnetic domain structures in Fe-3 wt.% Si, and of stacking faults in silicon and natural diamonds.

scholarly journals Magnetic properties of (Bi1−xLax)(Fe,Co)O3 films fabricated by a pulsed DC reactive sputtering and demonstration of magnetization reversal by electric field

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Munusamy Kuppan ◽  
Daichi Yamamoto ◽  
Genta Egawa ◽  
Sivaperuman Kalainathan ◽  
Satoru Yoshimura
Keyword(s):  
Electric Field ◽  
Magnetization Reversal ◽  
High Performance ◽  
Magnetic Domain ◽  
Magnetic Film ◽  
Film Plane ◽  
Force Microscopy ◽  
Domain Structures ◽  
Pulsed Dc ◽  
Submicron Scale

Abstract(Bi1−xLax)(Fe,Co)O3 multiferroic magnetic film were fabricated using pulsed DC (direct current) sputtering technique and demonstrated magnetization reversal by applied electric field. The fabricated (Bi0.41La0.59)(Fe0.75Co0.25)O3 films exhibited hysteresis curves of both ferromagnetic and ferroelectric behavior. The saturated magnetization (Ms) of the multiferroic film was about 70 emu/cm3. The squareness (S) (= remanent magnetization (Mr)/Ms) and coercivity (Hc) of perpendicular to film plane are 0.64 and 4.2 kOe which are larger compared with films in parallel to film plane of 0.5 and 2.5 kOe. The electric and magnetic domain structures of the (Bi0.41La0.59)(Fe0.75Co0.25)O3 film analyzed by electric force microscopy (EFM) and magnetic force microscopy (MFM) were clearly induced with submicron scale by applying a local electric field. This magnetization reversal indicates the future realization of high performance magnetic device with low power consumption.

Magnetic domain structures in multilayered NiFe films

1979 ◽  
Vol 50 (B3) ◽  
pp. 2384-2386 ◽  
Author(s):  
S. R. Herd ◽  
K. Y. Ahn
Keyword(s):  
Magnetic Domain ◽  
Domain Structures

Antiphase Domain Structures of CdTe on Sapphire Substrates

1987 ◽  
Vol 94 ◽  
Author(s):  
Kenji Maruyama ◽  
Mitsuo Yoshikawa ◽  
Hiroshi Takigawa
Keyword(s):  
Reaction Mechanism ◽  
Strong Correlation ◽  
Surface Reaction ◽  
Antiphase Domain ◽  
Cdte Layer ◽  
Single Domain ◽  
Rocking Curve ◽  
X Ray ◽  
Sapphire Substrates ◽  
Domain Structures

ABSTRACTAntiphase domain (APD) structures have been discovered in CdTe layers grown on (0001) sapphire substrates by MOCVD. To explain APD formation, an obstruction model based on a surface-reaction mechanism has been proposed. The proportion of one-phase domains to the total area varies with the [DETe]/[DMCd] ratio (VI/II ratio). A single-domain CdTe layer can be obtained at a VI/II ratio of 5. The APD structure shows a strong correlation with the crystallinity measured by X-ray. For a single-domain CdTe epilayer, theFWHM of the X-ray rocking curve shows 114 arc seconds and the EPD is 6×10 cm−2

The Influences of Depositing Angles on TbFe Film Magnetic and Magnetostrictive Characteristics

2005 ◽  
Vol 475-479 ◽  
pp. 3757-3760
Author(s):  
Hong Chuan Jiang ◽  
Wan Li Zhang ◽  
Bin Peng ◽  
Wen Xu Zhang ◽  
Shi Qing Yang
Keyword(s):  
External Field ◽  
Magnetic Domain ◽  
Grain Morphology ◽  
Dc Magnetron Sputtering ◽  
Easy Magnetization ◽  
Magnetization Direction ◽  
Saturation Field ◽  
Domain Structures ◽  
Columnar Grain ◽  
Easy Magnetization Direction

In this paper, the influences of depositing angles on TbFe film magnetic and magnetostrictive characteristics were discussed. TbFe films were deposited by DC magnetron sputtering. With the decrease of depositing angles from 900 to 150, TbFe film in-plane magnetization measured at 1600kA.m-1 external field is greatly increased. With the decrease of depositing angles from 900 to 150, the magnetostrictive saturation field is decreased. TbFe film in-plane magnetostriction is improved when depositing angles are changed from 900 to 150. Magnetic domain structures detected by MFM indicates that film easy magnetization direction is gradually changed from perpendicular to parallel with the decrease of depositing angles. The variation of film magnetic and magnetostrictive performances can be explained by the oblique anisotropy associated with columnar grain morphology of the films.

Spin-Polarized Scanning Electron Microscope for Analysis of Complicated Magnetic Domain Structures

1986 ◽  
Vol 25 (Part 2, No. 9) ◽  
pp. L758-L760 ◽  
Author(s):  
Kazuyuki Koike ◽  
Hideo Matsuyama ◽  
Katsuya Mitsuoka ◽  
Kazunobu Hayakawa
Keyword(s):  
Electron Microscope ◽  
Scanning Electron Microscope ◽  
Magnetic Domain ◽  
Domain Structures ◽  
Spin Polarized ◽  
Scanning Electron
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