Determination of the domain wall energy from hysteresis loops in YIG

1973 ◽  
Vol 59 (2) ◽  
pp. 447-454 ◽  
Author(s):  
M. Guyot ◽  
A. Globus
Keyword(s):  
Domain Wall ◽  
Hysteresis Loops ◽  
Domain Wall Energy

Determination of Intrinsic Magnetic Parameters of SmCo5 Phase in Sintered Samples

2005 ◽  
Vol 498-499 ◽  
pp. 129-133 ◽  
Author(s):  
Marcos Flavio de Campos ◽  
Fernando José Gomes Landgraf
Keyword(s):  
Powder Metallurgy ◽  
Domain Wall ◽  
Kerr Effect ◽  
Critical Diameter ◽  
Optical Microscope ◽  
Domain Theory ◽  
Magnetic Domains ◽  
Magnetic Parameters ◽  
Intrinsic Parameters

SmCo5 magnets are usually produced by powder metallurgy route, including milling, compaction and orientation under magnetic field, sintering and heat treatment. The samples produced by powder metallurgy, with grain size around 10 μm, are ideal for determination of intrinsic parameters. The first step for determination of intrinsic magnetic parameters is obtaining images of domain structure in demagnetized samples. In the present study, the domain images were produced by means of Kerr effect, in a optical microscope. After the test of several etchings, Nital appears as the most appropriate for observation of magnetic domains by Kerr effect. Applying Stereology and Domain Theory, several intrinsic parameters of SmCo5 phase were determined: domain wall energy 120 erg/cm2, critical diameter for single domain particle size 2 μm and domain wall thickness 60 Å. In the case of SmCo5, and also other phases with high magnetocrystalline anisotropy, Domain Theory presents several advantages when compared with Micromagnetics.

A HYBRID MODEL ON HYSTERESIS LOOP AND COERCIVITY IN NANOSTRUCTURED PERMANENT MAGNETS

2006 ◽  
Vol 05 (04n05) ◽  
pp. 627-631 ◽  
Author(s):  
M. J. SUN ◽  
G. P. ZHAO ◽  
J. LIANG ◽  
G. ZHOU ◽  
H. S. LIM ◽  
...  
Keyword(s):  
Thin Films ◽  
Domain Wall ◽  
Grain Boundary ◽  
Magnetic Moment ◽  
Permanent Magnets ◽  
Hysteresis Loops ◽  
Bulk Materials ◽  
Rotational Model ◽  
Moment Distribution ◽  
Coercivity Mechanism

A simplified micromagnetic model has been proposed to calculate the hysteresis loops of nanostructured permanent magnets for various configurations, including thin films, exchange-coupled double-layer systems and bulk materials. The reversal part of the hysteresis is based on the Stoner–Wohlfarth coherent rotational model and the coercivity mechanism is due mainly to the motion of the transition region (a domain wall like magnetic moment distribution in the grain boundary). The elements of nucleation and pinning models are also incorporated.

Determination of Electric and Magnetic Properties of Commercial LTCC Soft Ferrite Material

2011 ◽  
Vol 8 (1) ◽  
pp. 1-9 ◽  
Author(s):  
Nelu Blaž ◽  
Andrea Marić ◽  
Goran Radosavljević ◽  
Nebojša Mitrović ◽  
Ibrahim Atassi ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Low Frequency ◽  
Hysteresis Loops ◽  
Frequency Range ◽  
Dispersion Parameters ◽  
Simple Method ◽  
Component Design ◽  
Microwave Engineering ◽  
Characterization Procedure

This paper offers an effective, accurate, and simple method for permittivity and permeability determination of an LTCC (low temperature cofired ceramic) ferrite sample. The presented research can be of importance in the fields of ferrite component design and application, as well as for RF and microwave engineering. The characterization sample is a stack of LTCC tapes forming a toroid. Commercially available ferrite tape ESL 40012 was used and standard LTCC processing was applied for the sample fabrication. For the first time, the electrical properties of a ferrite toroid sample of ESL 40012 LTCC ferrite tape is presented at various frequencies. The electrical properties of LTCC ferrite materials, permittivity and specific resistivity, are shown in a frequency range from 10 kHz to 1 MHz using the capacitive method. The hysteresis properties of this material are also determined. B-H hysteresis loops were measured applying a maximum excitation of 2 kA/m and frequencies of 50 Hz, 500 Hz, and 1000 Hz. Permeability is determined in the frequency range from 10 kHz to 1 GHz and a characterization procedure is divided in two segments, for low and high frequencies. Low frequency measurements (from 10 kHz to 1 MHz) are performed using LCZ meter and discrete turns of wire, while a short coaxial sample holder and vector network analyzer were used for the higher frequency range (from 300 kHz to 1 GHz). In addition, another important factor required for the practical design of devices is presented, the temperature variation of the permeability dispersion parameters.

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