Irradiation-induced effects in yttrium—iron garnet films

Ubizskii, S.; Matkowskii, A.; Kuźma, M.

doi:10.1016/0304-8853(95)00977-9

Cited by 7 publications

(4 citation statements)

References 3 publications

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“…A great step forward in the application of the magneto-optical technique was the development of (Lu, Bi)-doped iron garnets with in-plane magnetization vectors (Wallenhorst et al 1995, Grechishkin et al 1996, Ubizskii et al 1996. To our knowledge these planar films were applied first to HTS by Dorosinskii et al (1991); see also (Belyaeva et al 1991a.…”

Section: Introductionmentioning

confidence: 99%

Magneto-optical studies of current distributions in high-T_csuperconductors

et al. 2002

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In the past few years magneto-optical flux imaging (MOI) has come to take an increasing role in the investigation and understanding of critical current densities in high-T c superconductors (HTS). This has been related to the significant progress in quantitative high-resolution magnetooptical imaging of flux distributions together with the model-independent determination of the corresponding current distributions. We review in this article the magneto-optical imaging technique and experiments on thin films, single crystals, polycrystalline bulk ceramics, tapes and melt-textured HTS materials and analyse systematically the properties determining the spatial distribution and the magnitude of the supercurrents. First of all, the current distribution is determined by the sample geometry. Due to the boundary conditions at the sample borders, the current distribution in samples of arbitrary shape splits up into domains of nearly uniform parallel current flow which are separated by current domain boundaries, where the current streamlines are sharply bent. Qualitatively, the current pattern is described by the Bean model; however, changes due to a spatially dependent electric field distribution which is induced by flux creep or flux flow have to be taken into account. For small magnetic fields, the Meissner phase coexists with pinned vortex phases and the geometry-dependent Meissner screening currents contribute to the observed current patterns. The influence of additional factors on the current domain patterns are systematically analysed: local magnetic field dependence of j c (B), current anisotropy, inhomogeneities and local transport properties of grain boundaries. We then continue to an overview of the current distribution and current-limiting factors of materials, relevant to technical applications like melt-textured samples, coated conductors and tapes. Finally, a selection of magneto-optical experiments which give direct insight into vortex pinning and depinning mechanisms are reviewed.

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Section: Introductionmentioning

confidence: 99%

Magneto-optical studies of current distributions in high-T_csuperconductors

et al. 2002

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“…Magnetic properties of iron garnet crystals in most cases are not sensitive enough to such concentration of point defects. Only in [42] the magnetooptical activity change was experimentally observed in Ga-substituted YIG epilayers after electron irradiation with energy of 3. . It is unlikely caused by the irradiation induced disordering process and, on the other hand, it does not occur at smaller doses of irradiation when recharging is observed in other garnet crystals.…”

Section: Introductionmentioning

confidence: 92%

Displacement Defect Formation in Complex Oxide Crystals under Irradiation

Ubizskii¹,

Matkovskii

Миронова-Улмане

et al. 2000

phys. stat. sol. (a)

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“…In a preceding investigation [1] we have studied the MAE spectrum of single crystalline yttrium iron garnet (YIG: Y 3 Fe 5 O 12 ) in the temperature range 4 K < T < 500 K. This work was begun (i) in view of the great technological importance of YIG on the fields of microwave applications [2,3] and magneto-optical thin film techniques [4,5], on the one hand, and (ii) because of the various, still open questions concerning a fundamental understanding of the interesting magneto-electric properties of this material [6 to 13], on the other hand. Thus, up to the presence, numerous techniques ± ± such as Mo È ssbauer effect [7,8,11], nuclear magnetic resonance [9], electric conductivity [10], dielectric [10] and magnetic relaxation (cf.…”

Section: Introductionmentioning

confidence: 99%

Charge Transport Mechanisms in Single Crystalline Yttrium Iron Garnet as Resolved by Magnetic Relaxations

Walz¹,

Torres

Íñiguez

et al. 2000

phys. stat. sol. (a)

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Single crystalline Yttrium Iron Garnet (YIG) has been irradiated at T % 80 K with 3 MeV electrons to a dose of ! 10 19 e À cm À2 and the recovery of the induced lattice damages, after systematic annealing over the temperature range 80 K < T a < 1400 K, is carefully investigated by means of magnetic after-effect (MAE) spectroscopy, covering the range 4 K < T < 500 K. The wide extension of recovery is attributed, besides to Fe 3 and Fe 2 interstitials and their associated d-and a-site vacancies, especially to the larger, and hence less mobile, Y 3 interstitialcies and their c-type vacant sites. The obtained data allow to resolve various charge transport mechanisms: (i) tunneling of electrons in combination with intra-atomic excitations in the low-temperature zone (4 K < T < 55 K); (ii) small-polaron hopping, extended over the range 80 K < T < 350 K; (iii) primarily radiation-induced, Debye-type ionic reorientation processes with peak temperatures near to 250, 325 and 400 K.Einkristalliner Yttrium-Eisen-Granat wurde bei T % 80 K mit 3 MeV-Elektronen auf eine Dosis von ! 10 19 e À cm À2 bestrahlt und die anschlieûende Erholung der Gitterfehler, nach systematischem Anlassen u È ber einen Temperaturbereich von 80 K < T a < 1400 K, mit Hilfe magnetischer Nachwirkungsspektroskopie im Gebiet 4 K < T < 500 K sorgfa È ltig untersucht. Der weit ausgedehnte Erholungsbereich wird, neben Fe 3 und Fe 2 Zwischengitter-Ionen und deren zugeho È riger d-und a-Platz Leerstellen, hauptsa È chlich den gro È ûeren, und damit unbeweglicheren, Y 3 ZwischengitterIonen und ihren c-Platz Leerstellen zugeordnet. Die gewonnenen Daten erlauben eine deutliche Unterscheidung folgender Ladungstransport-Vorga È nge: (i) Tunneln von Elektronen in Verbindung mit intra-atomarer Anregung (4 K < T < 55 K); (ii) Klein-Polaron-Hu È pfen im Bereich 80 K < T < 350 K; (iii) bestrahlungsinduzierte, durch Ionenspru È nge verursachte Debye-Prozesse mit Maximumtemperaturen von 250, 325 und 400 K.

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Irradiation-induced effects in yttrium—iron garnet films

Cited by 7 publications

References 3 publications

Magneto-optical studies of current distributions in high-T_csuperconductors

Magneto-optical studies of current distributions in high-T_csuperconductors

Displacement Defect Formation in Complex Oxide Crystals under Irradiation

Charge Transport Mechanisms in Single Crystalline Yttrium Iron Garnet as Resolved by Magnetic Relaxations

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Irradiation-induced effects in yttrium—iron garnet films

Cited by 7 publications

References 3 publications

Magneto-optical studies of current distributions in high-Tcsuperconductors

Magneto-optical studies of current distributions in high-Tcsuperconductors

Displacement Defect Formation in Complex Oxide Crystals under Irradiation

Charge Transport Mechanisms in Single Crystalline Yttrium Iron Garnet as Resolved by Magnetic Relaxations

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Magneto-optical studies of current distributions in high-T_csuperconductors

Magneto-optical studies of current distributions in high-T_csuperconductors