New Evidence of Interaction Between Grain and Boundaries Subsystems in Granular High-Temperature Superconductors

Balaev, D. A.; Semenov, S.; Gokhfeld, D. M.

doi:10.1007/s10948-021-05812-2

Cited by 11 publications

(10 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A characteristic property of granular superconductors, particularly high T c cuprates, is that they exhibit hysteresis in various transport properties, in particular magnetoresistance and critical current [25]. The physical origin of these effects is flux trapping in the intragranular and intergranular regions and is well understood [26][27][28][29].…”

Section: Granular Superconductorsmentioning

confidence: 99%

See 1 more Smart Citation

Granular Superconductivity in Hydrides Under Pressure

Hirsch

2022

J Supercond Nov Magn

View full text Add to dashboard Cite

It has been suggested that the measured magnetic properties of hydrides under pressure claimed to be high temperature superconductors indicate that the materials are granular superconductors. Such materials will show reduced or no magnetic field expulsion under field cooling, and will trap magnetic fields when the external magnetic field is removed. They will also exhibit hysteretic behavior in magnetoresistance and other transport properties. Here we point out that hysteresis in transport properties has never been reported for hydrides under pressure. Its presence, with the expected features, would indicate that the materials trap magnetic flux, hence that they can sustain persistent currents without dissipation, something that all superconductors can do. Conversely, its absence would indicate that these materials are not superconductors.

show abstract

Section: Granular Superconductorsmentioning

confidence: 99%

“…(b) Hysteresis cycle for the overall magnetization. (a) reproduced from ref [25],. (b) reproduced from ref [26]…”

mentioning

confidence: 99%

Granular Superconductivity in Hydrides Under Pressure

Hirsch

2022

J Supercond Nov Magn

View full text Add to dashboard Cite

show abstract

“…Дифрактограмма полученного образца показала только рефлексы, соответствующие структуре 1−2−3. Согласно результатам сканирующей электронной микроскопии (данные были получены на электронном микроскопе Hitachi-TM 4000), средний размер гранул составил 5 µm [44].…”

Section: экспериментunclassified

“…Отметим, что видимая на рис. 6 " густота" линий магнитной индукции в пространстве между гранулами отражает эффект сжатия потока в межгранульной среде гранулярного ВТСП, что проявляется в больших значениях параметра α, необходимых для описания экспериментального гистерезиса магнитосопротивления [23,[25][26][27][28][29]43,44]. Что касается перехода от эффективного поля к электросопротивлению, то R является функцией B eff , которое является функцией поля: R = f B eff (H) .…”

Section: концепция эффективного поля в межгранульной среде гранулярно...unclassified

Влияние Внутригранульных Мейсснеровских Токов И Захваченного В Гранулах Потока На Эффективное Поле В Межгранульной Среде И Гистерезис Магнитосопротивления Гранулярного ВТСП

Балаев¹,

Семенов²,

Гохфельд³

2022

Физика Твердого Тела

View full text Add to dashboard Cite

The concept of an effective field in an intergranular medium is used to describe the hysteresis magnetoresistance of granular HTSCs. This effective field is a superposition of the external magnetic field and the field induced by the magnetic moments of the superconducting granules. The magnetic moment of the granules is contributed by the shielding currents and the trapped magnetic flux. We studied and analyzed the effect of the trapped flux on the magnetoresistance. It has been experimentally shown that the dependence of the residual resistance (after applying of the external field) on the trapped flux clearly correlates with the behavior of the remanent magnetization. In addition, special attention was paid to a detailed comparison of the magnetoresistance of the granular YBa2Cu3O7-delta for two cases: (a) the magnetization of HTSC granules is caused only by the trapped magnetic flux (in a zero external field) and (b) HTSC granules are in the Meissner state (the external field is smaller than the first critical field of the granules). It has been found that Abrikosov vortices and intragranular Meissner currents differently affect the effective field in the intergranular medium (for the same values of magnetization for cases (a) and (b)). A possible reason for this difference is discussed.

show abstract

“…Для определения плотности критического тока из петли гистерезиса использовалось соотношение, следующее из модели критического состояния [65], ции от абрикосовских вихрей и мейсснеровских токов. Отметим, что " в чистом виде" влияние абрикосовских вихрей на B eff , а в конечном счете, на диссипацию, проявляется в наличии ненулевого сопротивления при H = 0 после приложения внешнего поля [29,35,[42][43][44][45][46][47][48][49], а также в релаксации остаточного сопротивления с течением времени (последнее связано с релаксацией намагниченности, вызванной выходом вихрей из сверхпроводника) [42,69]. В случае наличия парамагнитного вклада в ВТСП гранулах, также схематично показанного на рис.…”

Section: результаты и обсуждениеunclassified

Механизмы, определяющие гистерезис магнитосопротивления гранулярного ВТСП в присутствии парамагнитного вклада, на примере HoBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-delta-=/SUB=-

Семенов¹,

Gokhfeld²,

Терентьев³

et al. 2021

Физика Твердого Тела

View full text Add to dashboard Cite

The hysteretic magnetoresistance of granular high-temperature superconductor (HTSC) HoBa2Cu3O7-δ is investigated. Superconductors of the YBCO family with magnetic rare earth elements (Nd, Ho, Er, Sm, Yb, Dy) in place of yttrium are characterized by a significant paramagnetic contribution to the total magnetization. Impact of this paramagnetic contribution on the magnetotransport properties is analyzed using the concept of an effective field in an intergranular medium. Lines of magnetic induction from paramagnetic moments do not concentrate in intergranular boundaries, and, thus, have an insignificant effect on magnetotransport properties of granular HTSC. At the same time, there are strong concentration of magnetic flux in the intergranular boundaries due to Meissner currents and Abrikosov vortices. This magnetic flux compression determines the magnetotransport properties of granular HTSCs, including YBCO with magnetic rare earth elements.

show abstract

New Evidence of Interaction Between Grain and Boundaries Subsystems in Granular High-Temperature Superconductors

Cited by 11 publications

References 62 publications

Granular Superconductivity in Hydrides Under Pressure

Granular Superconductivity in Hydrides Under Pressure

Механизмы, определяющие гистерезис магнитосопротивления гранулярного ВТСП в присутствии парамагнитного вклада, на примере HoBa-=SUB=-2-=/SUB=-Cu-=SUB=-3-=/SUB=-O-=SUB=-7-delta-=/SUB=-

Contact Info

Product

Resources

About