• Journal of Magnetics
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• 제1권2호
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• pp.64-68
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• 1996

Compared with the conventional magnetostriction in Ni alloys which are in the order of several tens ppm (Parts Per Million =10-6), RFe$_2$(R = rare earth element) Laves Phase intermetallic compounds show large saturation magnetostriction in the range of a few thousands ppm. However, the large external magnetic field necessary to obtain saturatio magnetostriction has due to large magnetocrystalline anisotropy energy restrained the applicationof magnetostriction materials in RFe$_2$intermetallic compounds. As a result of its solution, the largest published value of effective giant magnetostriction in a low external magnetic field (less than a few hundred Oe) is reported in this paper by means of amorphisation of RFe$_2$intermetallic compounds with the addition of boron, as a half metal. For the amorphous (SmFe$_2$)0.97 B0.03 alloys, the effective magnetostriction of -545 and -610 $\times$ 10-6 is obtained at 400 and 1,000 Ie, respectively. Moreover, the effective magnetostriction of 590 and 630$\times$10-6 in the amorphous (TbFe$_2$)0.98 B0.02 alloys is also found at 400 and 1,000 Oe, respectively. This result will provide a clue to understanding the effect of half metal on anomalous increase of the effective giant magnetostriction and attract the great attention for magnetostriction applications.

• 한국자기학회지
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• 제18권4호
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• pp.159-162
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• 2008

자기변형(magnetostriction) 현상은 외부 온도와 자기장이 변할 때 자성체의 모양이나 부피가 변하는 현상이다. 반강자성을 갖는 희토류 원소와 화합물에서의 관측되는 자기변형 현상은 결정장에 의한 결정장 변형(crystal-field striction)과 교환상호작용에 의한 교환 변형(exchange striction)으로 잘 설명할 수 있음이 알려져 있다. 이 해설 논문에서는 결정장과 교환 상호작용을 포함하는 자기변형 표준이론에 대하여 논의하고자 한다.

• 한국자기학회지
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• 제5권5호
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• pp.726-729
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• 1995

We investigated the effects of Sm on the microstructure and magnetic properties of Fe-Co Alloy films prepared by a DC triode sputtering. The magnetostriction was found to be changed with the Sm content from positive to negative values, taking a zero magnetostriction was at about 3 at% Sm. The Sm content dependence of magnetostriction was explained by the formation of Sm enriched amorphous phase surrounding the main bcc (Fe,Co) crystalline phase, which was observed by a high resolution transmission electron microscopy.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2012년도 춘계학술대회 논문집
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• pp.1069-1070
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• 2012

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.275-278
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• 2002

The performance of Terfenol-D, the commercially available magnetostrictive material, is highly dependent on the prestress, magnetic field intensity and temperature. This paper presents an experimental investigation of the temperature effect on the magnetostriction in Terfenol-D. The effects of both prestress and magnetic field on the magnetostriction are also presented. Experimental results show that both the prestress and magnetic field on the magnetostriction are significant. It is also observed that the displacement decreases slightly to around 40$^{\circ}C$, then increases to 80$^{\circ}C$. It indicates that the displacement decreases due to the reduced magnetization, and increases due to the thermal expansion, as the temperature increases. It means that the reduced magnetization affects more in the displacement change up to 40$^{\circ}C$, and the thermal expansion affects more in the displacement change beyond 40$^{\circ}C$.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.772-773
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• 2015

This paper presents a dynamic model of 2-D magnetostriction in electrical steel sheet (ESS) under rotating flux magnetization conditions and its implementation in finite element method (FEM). For an arbitrary waveform of magnetic flux density (B), the corresponding magnetostriction waveform can be predicted by the model. In order to apply the model to FEM easily, the model is based on trilinear interpolation method. As an example, the model is applied to a three-phase transformer constructed by highly grain-oriented electrical steel sheets and the numerical results by the magnetostriction model are discussed.

• Journal of Magnetics
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• 제3권4호
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• pp.120-122
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• 1998

The higher order harmonic components of magnetostriction during ac magnetization in 3% SiFe are measured as a function of the magnetizing angle respect to [001] axis using a constructed laser interferometry. The magnetostriction with magnetizing angle from [001] axis agrees ith the calculation based on domain reorientation. The relative amplitudes of odd and even harmonics respectively for magnetic induction and magnetostriction decrease with the order of harmonics, accompanying the contraction of the amplitudes. The contraction of harmonics order of magnetostriction harmonics is shown to be the even number times of that of magnetic induction.

• 한국정밀공학회지
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• 제25권1호
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• pp.108-114
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• 2008

Recently, there have been several instances that the nuclear power plants were shut down due to the mechanical faults in the main transformer of the plants. These mechanical faults are primarily originated from the electromagnetically induced mechanical vibrations. Magnetostriction is identified to be the main cause of the mechanical vibration after analyzing the vibration data of the main transformers in nuclear power plants. In this study, we derived a mathematical model of the magnetostriction based on the Jiles-Atherton hysteresis model. The validity of the model is checked by matching the simulations with the experimental observations. The magnetostriction model used in this study will be the first step toward developing a design tool far the transformers that have minimal mechanical vibrations and are robust to mechanical faults.

• 전기학회논문지
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• 제63권8호
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• pp.1039-1045
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• 2014

Acoustic noise from a transformer, recently, has drawing more and more attentions. One of the main source of the noise is thought to be magnetostriction of the electrical steel sheets which compose transformer core. This paper deals with the magnetostriction of a highly grain-oriented electrical steel sheet measured by using a vector single sheet tester and a three-axial strain gauge. The results show that direction and axis ratio as well as the magnitude of the applied magnetic flux density contribute much to magnetostriction.

• 한국자기학회지
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• 제6권3호
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• pp.189-193
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• 1996

Magnetoresistance field sensitivity and magnetostriction were measured as a function of annealing temperature for NiFe/Ag multilayer systems displaying giant magnetoresistance. Key multilayer configurations such as number of NiFe/Ag bilayers and Ag spacer thickness were varied. A high giant magnetoresistance ratio up to 5% with zero magnetostriction and high magnetoresistance field sensitivity was possible to achieve simultaneously with optimal sample geometry and annealing condition.