scholarly journals FRACTAL ANALYSIS OF THE MAZE-LIKE DOMAIN STRUCTURE OF FERRITE-GARNET FILMS IN THE PROCESS OF MAGNETIZATION

2021 ◽  
pp. 134-145
Author(s):  
Александр Дмитриевич Зигерт ◽  
Галина Григорьевна Дунаева ◽  
Николай Юрьевич Сдобняков
Keyword(s):  
Fractal Dimension ◽  
Magnetic Hysteresis ◽  
Morphological Characteristics ◽  
Hysteresis Loops ◽  
Magnetic Films ◽  
Magnetic Hysteresis Loop ◽  
Gadolinium Gallium Garnet ◽  
Ferrite Garnet ◽  
Garnet Films ◽  
Iron Garnet

В данной работе с использованием комплекса экспериментальных методик и специализированного программного обеспечения исследуются магнитные висмутсодержащие феррит-гранатовые пленки, выращенные на подложках из гадолиний-галлиевого граната. Методом оптической магнитометрии получены предельные петли магнитного гистерезиса для дефектных и бездефектных участков висмутсодержащих феррит-гранатовых пленок. Установлено, что вдали от дефектов петля демонстрирует бескоэрцитивное поведение в пределах погрешности. Для случая перемагничивания вблизи дефекта появляется коэрцитивное состояние с H~1 Э. Для разных участков предельной петли магнитного гистерезиса определена фрактальная размерность. Полученные значения лежат в диапазоне D=1,35÷1,46 для произвольного участка пленки и D=1,37÷1,54 для участка с дефектами. Определены типичные морфологические характеристики поверхности висмутсодержащей ферритгранатовой пленки. Полученные результаты позволяют для эпитаксиальных висмутсодержащих магнитных пленок феррит-граната прогнозировать взаимосвязь между значением намагниченности и значением фрактальной размерности. In this work, using a set of experimental techniques and specialized software, magnetic bismuth-containing ferrite-garnet films grown on gadolinium-gallium garnet substrates are investigated. The limiting magnetic hysteresis loops are obtained by the method of optical magnetometry for defective and defect-free areas of bismuth-containing ferrite-garnet films. It was found that, far from defects, the loop exhibits a non-coercive behavior within the error limits. For the case of magnetization reversal, a coercive state with H ~1Oe appears near the defect. For different sections of the limiting magnetic hysteresis loop, the fractal dimension is determined. The obtained values are in the range of D=1,35÷1,46 for an arbitrary section of the film and D=1,37÷1,54 for a section with defects. Typical morphological characteristics of the surface of a bismuth-containing ferrite-garnet film have been determined. The results obtained make it possible to predict the relationship between the value of magnetization and the value of fractal dimension for epitaxial bismuth-containing magnetic films of iron garnet.

scholarly journals Developing a reference material set for the magnetic properties of NdFeB alloy-based hard magnetic materials

2019 ◽  
Vol 15 (1) ◽  
pp. 21-27
Author(s):  
E. A. Volegova ◽  
T. I. Maslova ◽  
V. O. Vas’kovskiy ◽  
A. S. Volegov
Keyword(s):  
Magnetic Properties ◽  
Magnetic Materials ◽  
Permanent Magnets ◽  
Magnetic Loss ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Magnetic Characteristics ◽  
Hard Magnetic Materials ◽  
Certified Values

Introduction The introduction indicates the need for the use of permanent magnets in various technology fields. The necessity of measuring the limit magnetic hysteresis loop for the correct calculation of magnetic system parameters is considered. The main sources of error when measuring boundary hysteresis loops are given. The practical impossibility of verifying blocks of magnetic measuring systems element-by-element is noted. This paper is devoted to the development of reference materials (RMs) for the magnetic properties of hard magnetic materials based on Nd2Fe14B, a highly anisotropic intermetallic compound.Materials and measuring methods Nd-Fe-B permanent magnets were selected as the material for developing the RMs. RM certified values were established using a CYCLE‑3 apparatus included in the GET 198‑2017 State Primary Measurement Standard for units of magnetic loss power, magnetic induction of constant magnetic field in a range from 0.1 to 2.5 T and magnetic flux in a range from 1·10–5 to 3·10–2 Wb.Results and its discussion Based on the experimentally obtained boundary hysteresis loops, the magnetic characteristics were evaluated, the interval of permitted certified values was set, the measurement result uncertainty of certified values was estimated, the RM validity period was established and the first RM batch was released.Conclusion On the basis of conducted studies, the RM type for magnetic properties of NdFeB alloy-based hard magnetic materials was approved (MS NdFeB set). The developed RM set was registered under the numbers GSO 11059–2018 / GSO 11062–2018 in the State RM Register of the Russian Federation.

Exchange Bias Properties in Bulk Ni45Co5Mn38Sn12 Heusler Alloy

2014 ◽  
Vol 875-877 ◽  
pp. 272-276 ◽  
Author(s):  
Chao Jing ◽  
Ye Jun Yang ◽  
Dong Hua Yu ◽  
Zhe Li ◽  
Xiao Long Wang ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Exchange Bias ◽  
Heusler Alloy ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Bias Field ◽  
Magnetic Hysteresis Loop ◽  
Zero Field ◽  
Co Substitution ◽  
Exchange Bias Field

We report the exchange bias properties in the bulk Ni45Co5Mn38Sn12quaternary Heusler alloy. The ferromagnetic (FM) –antiferromagnetic (AFM) interactions get reinforced after the Co substitution for Ni in the Ni-Mn-Sn alloy, which increase the exchange bias field (HE). A maximum shift in hysteresis loops of 306 Oe was observed in the 10 kOe field cooled sample. The origin of this large exchange bias field has been discussed. Magnetic hysteresis loop obtained in the zero field cooled (ZFC) mode shows double-shifted loop, and the reason of this phenomenon has been explained in detail.

Electric Field Driven Magnetic Domain Wall Motion in Iron Garnet Films

2009 ◽  
Vol 152-153 ◽  
pp. 143-146 ◽  
Author(s):  
A. Logginov ◽  
G. Meshkov ◽  
A. Nikolaev ◽  
E. Nikolaeva ◽  
A. Pyatakov ◽  
...  
Keyword(s):  
Domain Wall ◽  
Electric Field ◽  
Wall Motion ◽  
Magnetic Domain ◽  
Domain Wall Motion ◽  
Gadolinium Gallium Garnet ◽  
Magnetic Domain Wall ◽  
Garnet Films ◽  
Dynamic Observation ◽  
Iron Garnet

The room temperature magnetoelectric effect was observed in epitaxial iron garnet films that appeared as magnetic domain wall motion induced by electric field. The films grown on gadolinium-gallium garnet substrates with various crystallographic orientations were examined. The effect was observed in (210) and (110) films and was not observed in (111) films. Dynamic observation of the domain wall motion in 800 kV/cm electric field pulses gave the domain wall velocity in the range 30÷50 m/s. Similar velocity was achieved in magnetic field pulse about 50 Oe.

Thermal effects on magnetic hysteresis modeling

2012 ◽  
Vol 61 (1) ◽  
pp. 77-84 ◽  
Author(s):  
A. Ladjimi ◽  
M. Mékideche ◽  
A. Babouri
Keyword(s):  
Thermal Effects ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Effect Of Temperature ◽  
Temperature Dependent ◽  
Ferrite Material ◽  
Hysteresis Modeling ◽  
Dependent Model ◽  
Temperature Dependent Model

Thermal effects on magnetic hysteresis modelingA temperature dependent model is necessary for the generation of hysteresis loops of ferromagnetic materials. In this study, a physical model based on the Jiles-Atherton model has been developed to study the effect of temperature on the magnetic hysteresis loop. The thermal effects were included through a model of behavior depending on the temperature parametersMsandkof the Jiles-Atherton model. The temperature-dependent Jiles-Atherton model was validated through measurements made on ferrite material (3F3). The results have been found to be in good agreement with the model.

The linear relationship of spin pumping energy in a La:YIG/Pt heterostructure used in a microwave rectifier

MRS Advances ◽  
2019 ◽  
Vol 4 (09) ◽  
pp. 553-558 ◽  
Author(s):  
Yiheng Rao ◽  
Huaiwu Zhang ◽  
Dainan Zhang ◽  
Lichuan Jin ◽  
Qinghui Yang ◽  
...  
Keyword(s):  
Spin Current ◽  
Device Fabrication ◽  
Basic Material ◽  
Gadolinium Gallium Garnet ◽  
Spin Pumping ◽  
Garnet Films ◽  
Iron Garnet ◽  
Relationship Of ◽  
Spin Detection ◽  
Current Energy

ABSTRACTLa3+ doped yttrium iron garnet films have been grown on (111) oriented gadolinium gallium garnet substrates via Liquid phase epitaxy technique as a basic material for ISHE device fabrication. Pt as a material with a large spin hall angle was used as a spin detection layer. We investigated the dependence of the spin pumping effect on the power and frequency of the excitation microwaves in La:YIG/Pt bilayers by measuring the ISHE voltage. We demonstrated that the area under the ISHE curve(SISHE) across a wide power range had a nearly linear correlation with the input microwave power (Pin). The parameter SISHE can be used to describe the spin current energy in a Pt layer which can be a useful parameter for a microwave rectifier.

A Dissipative Quantum Dynamic Approach to Magnetic Hysteresis Loop and Magnetization Relaxation for Molecule Magnet Mn12

2003 ◽  
Vol 17 (17) ◽  
pp. 3215-3224
Author(s):  
Yuanchang Su ◽  
Yongjin Jiang
Keyword(s):  
Hysteresis Loop ◽  
Time Evolution ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Hysteresis Loop ◽  
Quantum Dynamic ◽  
Magnetization Relaxation ◽  
Resonant Tunnelling ◽  
State Evolution ◽  
Different Temperatures

A new approach to the magnetic hysteresis loop and magnetization relaxation of molecule magnet, Mn12, is presented. The method, so called "quasi-thermal equilibrium (QTE) + erase phase (EP)" (QTE + EP), leads the dissipation in state evolution. The method gives an method to approach an irreversible quantum dynamic tunnelling and time evolution of system and straightly leads the hysteresis loops. The QTE can work well for the double-well system and is able to be extended to the multi-wells quantum system. The EP is based on the physics of random interaction with the environment that results the phase de-coherence or say "re-initial" of the phase of quantum state during the time evolution. The stairs in the magnetic loops of Mn12 we have obtained quantitatively show the quantum resonant tunnelling. The relaxation of magnetization from initial lowest state is calculated for different temperatures and well shows the exponential behavior. The theoretical results well agree with the experiments.

Magnetoelastic Waves in Submicron Yttrium–Iron Garnet Films Manufactured by Means of Ion-Beam Sputtering onto Gadolinium–Gallium Garnet Substrates

2018 ◽  
Vol 63 (7) ◽  
pp. 1029-1035 ◽  
Author(s):  
Yu. V. Khivintsev ◽  
V. K. Sakharov ◽  
S. L. Vysotskii ◽  
Yu. A. Filimonov ◽  
A. I. Stognii ◽  
...  
Keyword(s):  
Yttrium Iron Garnet ◽  
Ion Beam ◽  
Gadolinium Gallium Garnet ◽  
Ion Beam Sputtering ◽  
Yttrium Iron ◽  
Garnet Films ◽  
Beam Sputtering ◽  
Iron Garnet ◽  
Magnetoelastic Waves

scholarly journals Observation of Negative Magnetic Hysteresis Loop in ZnO Thin Films

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Micah Haseman ◽  
Pooneh Saadatkia ◽  
David Winarski ◽  
Armando Hernandez ◽  
Matt Kusz ◽  
...  
Keyword(s):  
Hysteresis Loop ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Magnetic Hysteresis ◽  
Hysteresis Loops ◽  
Magnetic Behavior ◽  
Magnetic Hysteresis Loop ◽  
Structural Defects ◽  
Zno Films ◽  
Doped Zno

We report on the observation of an unusual negative magnetic hysteresis loop in ZnO thin film codoped with cobalt and aluminum (Co-Al:ZnO), while other transition-metal-doped ZnO films, such as Cu-doped ZnO and Mn-doped ZnO, exhibit normal hysteresis loops. The unusual magnetic behavior is ascribed to the presence of double magnetic layers with different magnetic moments due to the change of structural defects across the film layers. Positron annihilation measurements confirmed the presence of unique microstructural changes in the Co-Al:ZnO film. This study shows that defects in diluted magnetic semiconductors may induce not only ferromagnetism but also novel magnetic behaviors.

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