相关论文: Thermally-activated dynamics of spontaneous perpen…
We studied the high driving force regime of the current-voltage transport response in the mixed state of amorphous molybdenum-germanium superconducting films to the point where the flux flow becomes unstable. The observed nonlinear response…
The interplay between superconductivity and magnetism gives rise to many intriguing and exciting phenomena. In this Letter we report about a novel manifestation of this interplay: a temperature induced phase transition between different…
The work reported in my doctoral thesis is an experimental study of vortex dynamics and phase transitions in thin films of type II superconductors using scanning tunneling spectroscopy, low frequency ac susceptibility measurements and…
In Type II superconductors, the vortex lattice can exhibit "inverse melting," transitioning from a liquid to a crystalline solid as temperature increases. While recently observed via scanning tunneling microscopy in a 20 nm thick amorphous…
We show that under an a.c. magnetic field excitation the vortex lattice in a superconductor with periodic array of holes can undergo a transition from a Mott-like state where each vortex is localized in a hole, to a metal-like state where…
Recently, detailed real space imaging using scanning tunneling spectroscopy of the vortex lattice in a weakly pinned a-MoGe thin film revealed that the vortex lattice melts in two steps with temperature or magnetic field, going first from a…
Below the Curie temperature T_c of a Heusler-alloy film, consisting of densely packed, but exchange-decoupled nanograins, the spontaneous magnetization M_s(T) and static in-plane susceptibility \chi_{||}(T) increase very slowly signalizing…
In this thesis, we have studied the evolution of superconductivity in amorphous Molybdenum Germanium ($\textit{a}$-MoGe) thin films. The work can be broken down into two parts. In the first part, we investigate the effect of decreasing…
The behavior of a disordered amorphous thin film of superconducting Indium Oxide has been studied as a function of temperature and magnetic field applied perpendicular to its plane. A superconductor-insulator transition has been observed,…
In framework of Ginzburg-Landau model it is shown that narrow superconducting film with width w ~ 3-8 \xi(T) (\xi(T) is a temperature dependent coherence length) exhibits unusual transport properties. In the absence of bulk pinning its…
Using low-temperature Magnetic Force Microscopy (MFM) we provide direct experimental evidence for spontaneous vortex phase (SVP) formation in EuFe$_2$(As$_{0.79}$P$_{0.21}$)$_2$ single crystal with the superconducting $T^{\rm 0}_{\rm…
The mechanism of the interplay between superconductivity and magnetism is one of the intriguing and challenging problems in physics. Theory has predicted that the ferromagnetic order can coexist with the superconducting order in the form of…
We have numerically studied the statics and dynamics of a model three-dimensional vortex lattice at low magnetic fields. For the statics we use a frustrated 3D XY model on a stacked triangular lattice. We model the dynamics as a coupled…
Current-voltage (I-V) characteristics of quench condensed, superconducting, ultrathin Bi films in a magnetic field are reported. These show hysteresis for all films, grown both with and without thin Ge underlayers. Films on Ge underlayers,…
A vortex-induced transverse voltage in a superconducting film, previously predicted theoretically, has been seen experimentally for the first time. The magnitude of this voltage and its nonmonotonic current dependence are explained on the…
We use a two-coil mutual inductance technique to investigate the non-linear response of the vortex lattice of two type-II superconducting thin films, namely a very weakly pinned amorphous Molybdenum Germanium (a-MoGe) and a…
Longitudinal and transverse voltages have been measured on thin films of MgB2 with different superconducting transition widths. The study has been performed in zero and non-zero external magnetic fields. The non-zero transverse voltage has…
We review our studies of elastic lattices driven by an external force $F$ in the presence of random disorder, which correspond to the case of vortices in superconducting thin films driven by external currents. Above a critical force $F_c$…
We investigate the behavior of vortices of multi-component superconductivity, realized in $\rm{MgB_2}$ and Fe-based superconductors, within the framework of Ginzburg-Landau (GL) theory in terms of numerical calculations of the…
We analyze magnetic textures in a thin magnetic film and screening currents induced by these textures in a superconducting film. The films are supposed to be parallel and close to each other, but interact only via magnetic fields. We…