Related papers: Fishtail effect and vortex dynamics in LiFeAs sing…
Transverse ac permeability measurements in Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta }$ single crystals at low fields and temperatures in a vortex configuration free of external forces show that the decrease of the critical current as measured by…
The magnetic properties of LiFeAs, as single crystalline and polycrystalline samples, were investigated. The lower critical field deduced from the vortex penetration of two single crystals appears to be almost isotropic with a temperature…
We measure magnetization as a function of temperature, magnetic field and time in a BaFe$_2$(As$_{0.68}$P$_{0.32}$)$_2$ single crystal with $T_c$ = 27.6 K. The fish-tail observed on many $M$($H$) curves are used to construct isofield…
We present magnetization data on a weakly pinned CeRu_2 single crystal showing the existence of a stable state of the vortex lattice in the peak effect region. The stable state is achieved by cycling the magnetic field by small amplitude.…
LiFeAs is one of the iron-based superconductors having multiple gaps with the possible sign reversal. To clarify how those novel natures affect the energy dissipation of magnetic vortices, we investigated the microwave surface impedance of…
We report critical current density ($J_c$) in tetragonal FeS single crystals, similar to iron based superconductors with much higher superconducting critical temperatures ($T_{c}$'s). The $J_c$ is enhanced 3 times by 6\% Se doping. We…
The peak effect in weakly pinned superconductors is accompanied by metastable vortex states. Each metastable vortex configuration is characterized by a different critical current density J_c, which mainly depends on the past thermomagnetic…
We report on angle-resolved magnetization measurements on NdFeAsO$_{0.65}$F$_{0.35}$ (Nd-1111) single crystals. The field dependence of the critical current density, $J_c$, is non-monotonous in these crystals at all orientations and…
We report on the systematic evolution of vortex pinning behavior in isovalent doped single crystals of BaFe2(As1-xPx)2. Proceeding from optimal doped to ovedoped samples, we find a clear transfor- mation of the magnetization hysteresis from…
We present superconducting properties of single crystalline Ba(Fe$_{0.9}$Co$_{0.1}$)$_{2}$As$_{2}$ by measuring magnetization, resistivity, upper critical field, Hall coefficient, and magneto-optical images. The magnetization measurements…
Superconducting performance is tunable not only via chemical modification or defect engineering, but also through external parameters such as pressure, though this method remains less readily accessible. In this work, we study how…
The transport and magnetic studies are performed on high quality FeTe0.60Se0.40 single crystals to determine the upper critical fields (Hc2), lower critical field (Hc1) and the Critical current density (Jc). The value of upper critical…
$M(B)$-curves were experimentally investigated. Fishtail-effect (FE) was observed in MG YBa$_2$Cu$_3$O$_{7-\delta}$ and YBa$_2$Cu$_{3-x}$Ag$_x$O$_{7-\delta}$ (at $x \approx$ 0.02) crystals in a wide temperature range 40 K $<T<$ 75 K at the…
Magnetometry measurements in high quality LiFeAs single-crystals reveal a change in the sign of the magnetic hysteresis in the vicinity of the upper critical field $H_{c2}$, from a clear diamagnetic response dominated by the pinning of…
We report superconducting properties of single crystalline Ca10(Pt4-{\delta}As8)(Fe2-xPtxAs2)5 by X-ray diffraction, magnetization, resistivity, and magneto-optical imaging measurements. The magnetization measurements reveal fish-tail…
Three independent components of critical current density, one for the H//c axis and the other two for the H//ab plane, have been studied in CaKFe4As4 single crystals. When the magnetic field is applied along the c axis, we observed…
A sharp maximum in the critical current $J_c$ as a function of temperature just below the melting point of the Abrikosov flux lattice has recently been observed in both low and high temperature superconductors. This peak effect is strongest…
We present magnetic field dependence of the critical current density from dc-magnetization measurements concerning the anisotropic behavior of flux line lattice (FLL) in a single crystal of YNi_2B_2C. The peak effect (PE) phenomenon is…
We grew Lix(NH3)yFe2Te1.2Se0.8 single crystals successfully using the low-temperature ammonothermal method and the onset superconducting transition temperature Tc,onset is increased to 21 K when compared to 14 K in the parent compound…
The peak effect in critical current density J_c is investigated by studying the flux dynamics in V_3Si using bulk magnetometry, small-angle neutron scattering, and transport measurements on clean single-crystal samples from the same ingot.…