Complex Permeability of Ferrites Correlated with their Microstructure

2006 ◽  
Vol 45 ◽  
pp. 2560-2565 ◽  
Author(s):  
Janis Jankovskis
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Initial Permeability ◽  
The Other ◽  
Complex Permeability ◽  
Polycrystalline Ferrite

The totality of spinel and garnet polycrystalline ferrite (PF) samples is divided in two subgroups in process of their complex initial permeability (including the static value) relating to their microstructure (MS). The analysis for the first, including PF of rather perfect MS brings to explicit relations showing the effects of grain size distribution. For the other, the group of typical PF, the observed effects is possible to evaluate basing on the results gained for the first group.

Frequency Dependence of Complex Permeability of Polycrystalline Ferrites Based on the Realities of Microstructure

2013 ◽  
Vol 543 ◽  
pp. 507-510 ◽  
Author(s):  
Janis Jankovskis ◽  
Nikolajs Ponomarenko ◽  
Deniss Stepins
Keyword(s):  
Grain Size ◽  
Low Temperature ◽  
Frequency Dependence ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Complex Permeability ◽  
Absorption Component ◽  
Resonance Character ◽  
Explicit Relation

Complex permeability spectra of polycrystalline ferrites are analyzed on the basis of the model accounting for the effects of their grain size distribution (GSD). The model allows for explicit relation for absorption component. It shows, that by change of only one parameter (related with GSD) it is possible to turn from the relaxation to resonance character of spectrum, that spectra of ferrites, sintered at low temperature, tend to the most theoretical type - symmetrical one.

scholarly journals Environmental Forensic Study and Remediation Feasibility in an Abandoned Industrial Site

Proceedings ◽  
2018 ◽  
Vol 2 (23) ◽  
pp. 1503 ◽  
Author(s):  
Diego Baragaño ◽  
Eduardo Rodríguez-Valdés ◽  
Ana I. Peláez ◽  
Carlos Boente ◽  
Nora Matanzas ◽  
...  
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution ◽  
Arsenic Removal ◽  
Arsenic Speciation ◽  
Soil Washing ◽  
Industrial Area ◽  
The Other ◽  
Alkaline Soils ◽  
Fertilized Soil

An environmental forensic study was developed in a former industrial area in southern Spain. Previous information about the site revealed arsenic and hydrocarbons affection exceeding soil screening levels. A full characterisation of arsenic affection was thus performed. In this regard, the bioavailable fractions, arsenic speciation and grain-size distribution were determined. Two different polluted types of soils/fillers were identified. The first one is affected by non-bioavailability As(V) concentrations on the finer fraction, and the other one is affected by As(III) and As(V) with higher bioavailability than the other case, affecting all grain-size fractions homogeneously. Notably the textures are very heterogeneous within the site. On the other hand, hydrocarbons affection was also studied. Cuantitative and cualitative organic analyses revealed the presence of organic products with differing degree of degradation (naphthas). An additional microbiological study revealed regular microbial counts for a non-fertilized soil, and an edaphological characterization showed alkaline soils with low levels of nutrients and natural organic matter. The information gathered was used to evaluate remediation feasibility. Soil washing was selected as an interesting possibility for arsenic removal, although grain-size distribution must be studied carefully because of high variability. As regards as organics, bioremediation is a valuable option due to the suitable microbiology and the type of hydrocarbons found, together with the usual low costs of techniques such as landfarming or biopiles.

Grain size distribution in evaporated permalloy films

1970 ◽  
Vol 2 (2) ◽  
pp. K69-K73 ◽  
Author(s):  
M. Reinbold ◽  
H. Hoffmann
Keyword(s):  
Grain Size ◽  
Size Distribution ◽  
Grain Size Distribution

scholarly journals The Domain and Microstructure of Resin-Bonded Magnets

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2849
Author(s):  
Marcin Jan Dośpiał
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Grain Size ◽  
Size Distribution ◽  
Domain Structure ◽  
Grain Size Distribution ◽  
Exchange Interactions ◽  
Force Microscopy ◽  
Transmission Electron ◽  
Scanning Electron

This paper presents domain and structure studies of bonded magnets made from nanocrystalline Nd-(Fe, Co)-B powder. The structure studies were investigated using scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), Mössbauer spectroscopy and X-ray diffractometry. On the basis of performed qualitative and quantitative phase composition studies, it was found that investigated alloy was mainly composed of Nd2(Fe-Co)14B hard magnetic phase (98 vol%) and a small amount of Nd1.1Fe4B4 paramagnetic phase (2 vol%). The best fit of grain size distribution was achieved for the lognormal function. The mean grain size determined from transmission electron microscopy (TEM) images on the basis of grain size distribution and diffraction pattern using the Bragg equation was about ≈130 nm. HRTEM images showed that over-stoichiometric Nd was mainly distributed on the grain boundaries as a thin amorphous border of 2 nm in width. The domain structure was investigated using a scanning electron microscope and metallographic light microscope, respectively, by Bitter and Kerr methods, and by magnetic force microscopy. Domain structure studies revealed that the observed domain structure had a labyrinth shape, which is typically observed in magnets, where strong exchange interactions between grains are present. The analysis of the domain structure in different states of magnetization revealed the dynamics of the reversal magnetization process.

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