Direct observation of nanoscale interface phase in the superconducting chalcogenide K$_{x}$Fe$_{2-y}$Se$_2$ with intrinsic phase separation
| Autor: | Ricci, A., Poccia, N., Joseph, B., Innocenti, D., Campi, G., Zozulya, A., Westermeier, F., Schavkan, A., Coneri, F., Bianconi, A., Takeya, H., Mizuguchi, Y., Takano, Y., Mizokawa, T., Sprung, M., Saini, N. L. |
|---|---|
| Rok vydání: | 2015 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 91, 020503(R) (2015) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.91.020503 |
| Popis: | We have used scanning micro x-ray diffraction to characterize different phases in superconducting K$_{x}$Fe$_{2-y}$Se$_2$ as a function of temperature, unveiling the thermal evolution across the superconducting transition temperature (T$_c\sim$32 K), phase separation temperature (T$_{ps}\sim$520 K) and iron-vacancy order temperature (T$_{vo}\sim$580 K). In addition to the iron-vacancy ordered tetragonal magnetic phase and orthorhombic metallic minority filamentary phase, we have found a clear evidence of the interface phase with tetragonal symmetry. The metallic phase is surrounded by this interface phase below $\sim$300 K, and is embedded in the insulating texture. The spatial distribution of coexisting phases as a function of temperature provides a clear evidence of the formation of protected metallic percolative paths in the majority texture with large magnetic moment, required for the electronic coherence for the superconductivity. Furthermore, a clear reorganization of iron-vacancy order around the T$_{ps}$ and T$_c$ is found with the interface phase being mostly associated with a different iron-vacancy configuration, that may be important for protecting the percolative superconductivity in K$_{x}$Fe$_{2-y}$Se$_2$. Comment: 6 pages, 4 figures |
| Databáze: | arXiv |
| Externí odkaz: |
|