Single-Domain Wall Propagation and Damping Mechanism during Magnetic Switching of Bistable Amorphous Microwires

Varga, R.; Garcia, K.; Vázquez, M.; Vojtaník, P.

doi:10.1103/physrevlett.94.017201

Cited by 132 publications

(100 citation statements)

References 25 publications

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“…An important problem is to establish the way and conditions for reversing the orientation of the magnetization. Although the reversal process is well known for ferromagnetic nanowires, 6,7,8,9,10 the equivalent phenomenon in nanotubes has been poorly explored so far in spite of some potential advantages over solid cylinders. Nanotubes exhibit a core-free magnetic configuration leading to uniform switching fields, guaranteeing reproducibility, 4,5 and due to their low density they can float in solutions making them suitable for applications in biotechnology (see [1] and refs.…”

mentioning

confidence: 99%

“…Since the nucleation of a domain wall is more likely to occur at the ends, and we wish to follow the propagation of a single wall, 6 the field has not been applied to the last 12 nm of one end, following a pinning procedure used in experiments with microwires. For every β we tried |H a | = 1.3, 1.5 and 1.7 kOe, without any significant difference in the results.…”

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confidence: 99%

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Reversal modes in magnetic nanotubes

Landeros

Allende

Escrig

et al. 2007

Applied Physics Letters

217

200

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The magnetic switching of ferromagnetic nanotubes is investigated as a function of their geometry. Two independent methods are used: Numerical simulations and analytical calculations. It is found that for long tubes the reversal of magnetization is achieved by two mechanism: The propagation of a transverse or a vortex domain wall depending on the internal and external radii of the tube.During the last decade, interesting properties of magnetic nanowires have attracted great attention. Besides the interest in their basic properties, there is evidence that they can be used in the production of new devices. More recently magnetic nanotubes have been grown 1,2,3,4 motivating a new research field. Magnetic measurements, 3 numerical simulations 4 and analytical calculations 5 on such tubes have identified two main states: an in-plane magnetic ordering, namely the fluxclosure vortex state, and a uniform state with all the magnetic moments pointing parallel to the axis of the tube. An important problem is to establish the way and conditions for reversing the orientation of the magnetization. Although the reversal process is well known for ferromagnetic nanowires, 6,7,8,9,10 the equivalent phenomenon in nanotubes has been poorly explored so far in spite of some potential advantages over solid cylinders. Nanotubes exhibit a core-free magnetic configuration leading to uniform switching fields, guaranteeing reproducibility, 4,5 and due to their low density they can float in solutions making them suitable for applications in biotechnology (see [1] and refs. therein).Let us consider a ferromagnetic nanotube in a state with the magnetization M along the tube axis. A constant and uniform magnetic field is then imposed antiparallel to M. After some delay time the magnetization reversal (MR) will start at any end. MR or magnetic switching can occur by means of different mechanisms, depending on the geometrical parameters of the tube. In this paper we will focus on the reversal process by means of two different but complementary approaches: numerical simulations and analytical calculations. Their mutual agreement sustains the results reported in this study.Numerical Simulations. Geometrically, tubes are characterized by their external and internal radii, R and a respectively, and height, H. It is convenient to define the ratio β ≡ a/R, so that β = 0 represents a solid cylinder and β → 1 correspond to a very narrow tube. The internal energy, E, of a nanotube with N magnetic moments can be written aswhere E ij is the dipolar energy given by E ij = µ i · µ j − 3(µ i ·n ij )(µ j ·n ij ) /r 3 ij , with r ij the distance between the magnetic moments µ i and µ j ,μ i the unit vector along the direction of µ i andn ij the unit vector along the direction that connects µ i and µ j . J ij = J is the exchange coupling constant between nearest neighbors and J ij = 0 otherwise. E a = − N i=1 µ i · H a is the contribution of the external magnetic field. In this paper we are interested in soft magnetic materials, in which case anisotropy can be s...

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confidence: 99%

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Reversal modes in magnetic nanotubes

Landeros

Allende

Escrig

et al. 2007

Applied Physics Letters

217

200

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“…Ферромагнитные микропровода с аморфной или на-нокристаллической структурой имеют ряд специфиче-ских магнитных свойств: наличие двух устойчивых со-стояний намагниченности (бистабильность), высокую подвижность доменов и гигантский магнитный импе-данс (МИ) [1][2][3][4][5][6].…”

Section: Introductionunclassified

Влияние механических напряжений и отжига на магнитную структуру и магнитоимпеданс аморфных CoFeSiBCr микропроводов

Неъматов¹,

Салем²,

Азим³

et al. 2018

Физика Твердого Тела

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Структурные и магнитные свойства аморфных ферромагнитных микропроводов могут претерпевать значительные изменения в результате воздействия внешних механических напряжений и температурной обработки. Изучение происходящих при этом трансформаций представляется важным как для разработки различных сенсоров механических напряжений, нагрузки, температуры, так и для индуцирования в проводах определенного типа магнитной анизотропии, играющей значительную роль в осуществлении в них различных эффектов. В настоящей работе исследовано влияние внешних напряжений и отжига на процессы намагничи-вания и магнитный импеданс в микропроводах состава Co 71 Fe5B 11 Si 10 Cr 3 , которые в аморфном состоянии имеют невысокую положительную магнитострикцию (порядка 10 −8 ). Воздействие внешних напряжений приводит к резкому изменению характера кривой перемагничивания, что обусловлено изменением знака магнитострикции и типа магнитной анизотропии. Соответственно амплитуда высших гармоник и величина магнитного импеданса оказываются чувствительными к механическим напряжениям. В проводах с частичной кристаллизацией действие упругих напряжений не приводит к заметному изменению магнитных свойств, однако с помощью отжига можно добиться существенного увеличения осевой магнитной анизотропии проводов, находящихся в напряженном состоянии. Экспериментальные результаты проанализированы в рамках магнитострикционной модели наведенной магнитной анизотропии.

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“…Particularly, in the case of positive magnetostriction microwires, the domain structure consists of single large internal domain with axial magnetization, which is surrounded by the external, radially magnetized, multidomain structure (see Figure 1) [4]. As a result, magnetization process in axial direction runs through the depining and subsequent propagation along entire microwire of a domain wall from the closure domain shown in figure 1 [3]. Such magnetization process results in bistability (e.g.…”

Section: Introductionmentioning

confidence: 99%

“…Amorphous magnetic glass-coated microwires are novel materials with outstanding magnetic behavior for micromagnetism studies with high potential for technological applications [1,2,3]. They consist of a magnetic nucleus (which diameter ranges between 1 and 30 µm) coated by a Pyrex-like glass (2 to 20 µm thick), and they are prepared by quenching and drawing technique.…”

Section: Introductionmentioning

confidence: 99%

Bistable FeCoMoB microwires with nanocrystalline microstructure and increased Curie temperature

Klein¹,

Varga²,

Vojtaník³

et al. 2010

J. Phys. D: Appl. Phys.

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To cite this version:P Klein, R Varga, P Vojtanik, J Kovac, J Ziman, et al. They combine advantages of nanocrystalline alloys exhibiting simultaneously increased Curie temperature and magnetic bistability, which is required for modern sensoric and spintronic devices. Positive magnetostriction of the crystalline FeCo grains results in a magnetic bistability, whereas good soft magnetic properties remains stabilized. As a result of mechanical stress induced by the glass-coating, the optimum temperature range for thermal treatment is enhanced up to 600 o C.

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Single-Domain Wall Propagation and Damping Mechanism during Magnetic Switching of Bistable Amorphous Microwires

Cited by 132 publications

References 25 publications

Reversal modes in magnetic nanotubes

Reversal modes in magnetic nanotubes

Влияние механических напряжений и отжига на магнитную структуру и магнитоимпеданс аморфных CoFeSiBCr микропроводов

Bistable FeCoMoB microwires with nanocrystalline microstructure and increased Curie temperature

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