Zhonghao Liu

Suppression of superconducting critical current density by small flux jumps in MgB2 thin films

By doing magnetization measurements during magnetic field sweeps on thin films of the new superconductor MgB2, it is found that in a low-temperature and low-field region small flux jumps are taking place. This effect strongly Suppresses the central magnetization peak leading to reduced nominal superconducting critical current density at low temperatures, A borderline for this effect to occur is determined on the field-temperature (H-T) phase diagram. It is suggested that the small size of the flux jumps in films is due to the higher density of small defects and the relatively easy thermal diffusion in thin films in comparison with bulk samples.

Influence of carbon concentration on the superconductivity in MgCxNi3

The influence of carbon concentration on the superconductivity (SC) in MgCxNi3 has been investigated by measuring the low temperature specific heat combined with first principles electronic structure calculation. It is found that the specific heat coefficient gamma(n) = C-en/T of the superconducting sample (xapproximate to1) in normal state is twice that of the non-superconducting one (xapproximate to0.85). The comparison of measured gamma(n) and the calculated electronic density of states (DOS) shows that the effective mass renormalization changes remarkably as the carbon concentration changes. The large mass renormalization for the superconducting sample and the low transition temperature T-c(7K) indicate that more than one kind of boson mediated electron-electron interaction exists in MgCxNi3.

Linear temperature dependence of lower critical field in MgB2

The lower critical field

Intrinsic percolative superconductivity in heavily overdoped high-temperature superconductors

H_{c1}

Competition between BCS superconductivity and ferromagnetic spin fluctuations in MgCNi3

has been carefully measured on a well shaped cylindrical sample of the new superconductor

Two-dimensional feature of the Nernst effect in normal state of underdoped La2 − xSrxCuO4 single crystals

MgB_2

Bulk evidence for s-wave pairing symmetry in electron-doped infinite-layer cuprate Sr0.9La0.1CuO2

fabricated by high pressure synthesis. The penetration depth

Sudden gap closure across the topological phase transition in Bi 2 − x In x Se 3

lambda

Experimental observation of bulk nodal lines and electronic surface states in ZrB2

is calculated from the

Large intrinsic anomalous Hall effect in half-metallic ferromagnet Co 3 Sn 2 S 2 with magnetic Weyl fermions

H_{c1}