Three-Dimensional Strain Model for Various Kinds of $\hbox{Nb}_{3}\hbox{Sn}$  Wires
The three-dimensional strain dependence of the superconducting property for an internal-tin Nb<sub>3</sub>Sn wire was investigated, because three-dimensional strains are necessary to understand the strain effect of superconducting properties for Nb<sub>3</sub>Sn wires. The three-dimensional strain dependence of <i>B</i><sub>c2</sub> and residual strains were measured by the strain gauge method and neutron diffraction, experimentally. As a result, the three-dimensional strain model based on the experimental results for bronze route Nb<sub>3</sub>Sn wires explained the strain dependence of superconducting properties for an internal-tin Nb<sub>3</sub>Sn wire. We found that the strain effect of <i>B</i><sub>c2</sub> for bronze route and internal-tin Nb<sub>3</sub>Sn wires are expressed by three-dimensional strain model.