اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدControlled suppression of local magnetization hysteresis by dc in-plane field in Bi2Sr2CaCu2O8
55
0
0.0
(
0
)
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
Local magnetization hysteresis is among the most extensively studied features of high-temperature superconductors (HTSC). The usual source of hysteresis in superconductors is bulk vortex pinning due to material defects. Two additional known mechanisms of magnetic irreversibility are the Bean-Livingston surface barrier and the geometrical barrier (GB). GB arises due to a competition between the line energy of a vortex penetrating into the sample and the Lorentz force of Meissner currents which focuses vortices in the samples center to form a dome-shaped vortex distribution. This work demonstrates that dc in-plane field overcomes hysteresis mainly through the GB suppression in a region of phase diagram under consideration (high temperatures and low fields).
قيم البحث
اقرأ أيضاً
We study voltage response of nano-bridge based DC-SQUID fabricated on a Si_{3}N_{4} membrane. Such a configuration may help in reducing 1/f noise, which originates from substrate fluctuating defects. We find that the poor thermal coupling between the
DC-SQUID and the substrate leads to strong hysteretic response of the SQUID, even though it is biased by an alternating current. In addition, when the DC-SQUID is biased near a threshold of spontaneous oscillations, the measured voltage has an intermittent pattern, which depends on the applied magnetic flux through the SQUID.
We report on theoretical studies on ferromagnetic superconductors, URhGe, and UCoGe and identifies the pairing state as a non-unitary spin-triplet one, analogous to superfluid $^3$He-A phase. A recently found superconductor UTe$_2$ with almost ferrom
agnet is analyzed by the same manner. Through investigating their peculiar upper critical field $H_{rm c2}$ shapes, it is shown that the pairing symmetry realized in all three compounds can be tuned by their magnetization curves under applied fields. This leads to the reentrant $H_{rm c2}$ in URhGe, an S-shaped in UCoGe and an L-shaped $H_{rm c2}$ in UTe$_2$ observed under the field direction parallel to the magnetic hard axis in orthorhombic crystals in common. The identification with double chiral form: ${bf d}(k)=(hat{b}+ihat{c})(k_b+ik_c)$ in UTe$_2$ naturally enables us to understand (1) multiple phases with A$_1$, A$_2$, and A$_0$ phases observed under pressure, (2) the enhanced reentrant $H_{rm c2}$ for the off-axis direction fields associated with first order meta-magnetic transition, and (3) Weyl point nodes oriented along the $a$-axis. All three compounds are found to be topologically rich solid-state materials worth further investigation.
Little-Parks effect names the oscillations in the superconducting critical temperature as a function of the magnetic field. This effect is related to the geometry of the sample. In this work, we show that this effect can be enhanced and manipulated b
y the inclusion of magnetic nanostructures with perpendicular magnetization. These magnetic nanodots generate stray fields with enough strength to produce superconducting vortex-antivortex pairs. So that, the L-P effect deviation from the usual geometrical constrictions is due to the interplay between local magnetic stray fields and superconducting vortices. Moreover, we compare our results with a low-stray field sample (i.e. with the dots in magnetic vortex state) showing how the enhancement of the L-P effect can be explained by an increment of the effective size of the nanodots.
A controlled local enhancement of superconductivity yields unexpected modifications in the vortex dynamics. This local enhancement has been achieved by designing an array of superconducting Nb nanostructures embedded in a V superconducting film. The
most remarkable findings are: i) vanishing of the main commensurability effect between the vortex lattice and the array unit cell, ii) hysteretic behavior in the vortex dynamics, iii) broadening of the vortex liquid phase and iv) strong softening of the vortex lattice. These effects can be controlled and they can be quenched by reducing the Nb array superconducting performance applying an in-plane magnetic field. These results can be explained by taking into account the repulsive potential landscape created by the superconducting Nb nanostructures on which vortices move.
We observe two types of superconducting states controlled by orientations of local wrinkles on the surface of LiFeAs. Using scanning tunneling microscopy/spectroscopy, we find type-I wrinkles enlarge the superconducting gaps and enhance the transitio
n temperature, whereas type-II wrinkles significantly suppress the superconducting gaps. The vortices on wrinkles show a C2 symmetry, indicating the strain effects on the wrinkles. A discontinuous switch of superconductivity occurs at the border between two different wrinkles. Our results demonstrate that the local strain effect could affect superconducting order parameter of LiFeAs with a possible Lifshitz transition, by alternating crystal structure in different directions.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
