Lan Jian

Magnetic and 57Fe Mössbauer study of YFe12-xVx compounds

Using Mossbauer spectroscopy and magnetic measurement, the hyperfine coupling coefficient of YFe12-xVx (x=2,3,4) was determined approximately Ā=14.85T/μB. The reasons of changes of the hyperfine parameters depending on the concentration of vanadium atom were also discussed.

Crystallographic and Magnetic Properties of R2Fe17Cx with R=Y, Pr, Nd, Sm, Gd, Dy, and Er

A series of R2Fe17Cx compounds (R = Y, Pr, Nd, Sm, Gd, Dy, and Er; x = 0, 0.5 and 1.0) were synthesized. X-ray diffraction analyses showed that the crystal structure is rhombohedral Th2Zn17 type for R = Pr, Nd, Sm, and Gd. For R = Y, Dy and Er, a structure transformation from hexagonal Th2Ni17 type (x = 0.5) to rhombohedral Th2Zn17 type (x = 1.0) was observed. The introduction of C into R2Fe17 leads to an expansion of the lattice. It strongly enhances Curie temperature. C atoms occupy interstitially the nearest neighbour sites to the R atoms in the lattice. The anisotropy of R sublattice was strengthened. A uniaxial anisotropy was observed in Sm2Fe17C0.5 at room temperature.

Ge Film Contacts to Radio Frequency Sputtered Y-Ba-Cu-O Superconductor Film

The semiconductor-superconductor contact system of Ge/Y-Ba-Cu-O (YBCO)/SrTiO3 has been successfully fabricated by two steps of deposition. The YBCO film in the contact of Ge/YBCO did not lose its superconductivity and its Tc (on set) did not degrade as well. The top layer of Ge was polycrystalline with preferred orientation corresponding to the epitaxial structure of the underlayer of YBCO.

Superconductivity of Tl2Ba2(Ca1-xMgx)2Cu3 Oy

The structural, magnetic and superconducting properties of the Tl2Ba2 (Ca1-xMgx)2Cu3Oy system with x=0, 0.05, 0.1, 0.15, 0.2, 0.3, 0.4, 0.5 were studied. Replacement of calcium by magnesium depresses Tc from 116.3K (x=0) to 93.3K (x=0.5). The critical current also decreases with increasing x.

Magnetic structure and transition of amorphous NdxNi1-x thin films

The magnetic properties of NdxNi1-x amorphous thin films were studied. It was found that the effective magnetic moment of Ni atom(Ni) approached to zero at X ≥ 0.26, and when X<0.26 the composition dependence of Ni followed approximately Ni=(0.6-3X1.2)μB. It is found that the asperomagnetic and speromagnetic structures coexist in the amorphous Nd-Ni films with X<0.26, and only speromagnetic structure exists for X ≥ 0.26.