EXAFS study of clustering of Mn in Al-Mn based transition edge sensor*

Transition edge sensors are designed for space exploration by offering high spectral resolving power over a broad band with miniaturized size. A key enabling component for such kind of sensor will be microwave kinetic inductance detectors (MKIDs). The MKID contains the superconducting resonator that responds to thermal fluctuation from radiation input. The Al-Mn alloy based detectors developed by NASA Goddard are favorably showing the shifting of the critical temperature. The detectors, annealed at higher temperature, are tending to decrease critical temperature Tc. Using extended x-ray absorption fine spectroscopy (EXAFS), we studied clustering of the Mn dopants in Al. We found that the clustering of Mn increases with increasing annealing temperature.