Polycrystalline samples of a new superconducting EuAsFeO0,85F0,15 compound with critical temperature <$E T sub c> = 11 K were prepared by solid state synthesis. Its electric and magnetic properties have been investigated in magnetic fields from 0,1 to 140 000 Oe. Critical magnetic fields <$E H sub c1>, and <$E H sub c2> were measured and hence the magnetic penetration depths l and the coherence length x have been estimated. The temperature dependence <$E H sub c2 (T)> exhibits clear hyperbolic - type behavior starting with the lowest fields. The data derived were used to estimate probable high <$E T sub c> and <$E H sub c2> in compounds doped with rare-earths having small atomic radii.

The Andreev reflection spectra dI/dV(V) of the magnetic superconductor Dy0,6Y0,4Rh3,85Ru0,15B4 have been investigated. Pronounced stimulation of superconductivity by an external magnetic field has been observed for the first time. The effect showed up as enhancement of the gap structure (and hence the gap itself) in the spectra and its shift towards higher voltages with an increasing field. In the intermediate fields the structure also behaved strangely: instead of the usual smooth decrease with a grooving field, the gap features dropped abruptly near the critical point <$E H sub c 2>. Of interest is also the abnormally high relative gap value <$E 2 DELTA "/" k sub B T sub c~symbol Ы~4> (as compared to conventional singlet superconductors) which was found for some contacts from a comparison of experimental spectra and the modified Blonder - Tinkham - Klapwiyk theory. We attribute the features revealed in the point-contact spectroscopic investigations of Dy0,6Y0,4Rh3,85Ru0,15B4 in a magnetic field to the triplet-type Cooper pairing in the compound because only in this case one can expect the stimulation of superconductivity in the stationary magnetic fields up to ~ <$E 0,7 H sub c 2>.

Індекс рубрикатора НБУВ: В368.313

Рубрики:

Магнітні властивості надпровідників

Шифр НБУВ: Ж14063 Пошук видання у каталогах НБУВ 
Повний текст  Наукова періодика України 

Influence of predeformation by the equal-channel multiangle pressing combined with hydroextrusion, drawing and heat treatment on structure and physico-mechanical properties of superconducting Mb + 60 at. % Ti alloy wire has been investigated. Effect of deformation on pinning force in the alloy has been estimated.

In the paper we present the results of the ac susceptibility measurements of two newly discovered superconducting diboride - MgB2.

Исследовано влияние равноканального многоуглового прессования в комбинации с гидроэкструзией и волочением, а также заключительной термообработкой на плотность критического тока, силу пиннинга и температуру сверхпроводящего перехода биметаллического провода на основе сплава Nb + 60 ат. % Ti.

Исследованы температурные и полевые зависимости намагниченности нанокомпозитного соединения GdNiO3 в интервале температур 0,5 - 150 K в магнитных полях до 14 Тл, а также температурные зависимости теплоемкости в магнитных полях до 9 Тл. Обнаружены аномалии статической восприимчивости, теплоемкости и динамической намагниченности при температурах 0,7, 1,6 и 13 K соответственно. Обнаруженные аномалии связываются с магнитными фазовыми переходами.