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A Kirnbauer, C. Spadt, C. Koller, S. Kolozsvári, P.H. Mayrhofer:
"High-entropy oxide thin films based on Al-Cr-Nb-Ta-Ti";
Vacuum, 168 (2019).

Single-phase crystalline (Al,Cr,Nb,Ta,Ti)O2 high-entropy oxide thin films were synthesized at 400 °C by reactive magnetron sputtering of an equimolar Al-Cr-Nb-Ta-Ti-compound target. These show similar chemistry as well as the same rutile structure, even when varying the relative oxygen flow-rate ratio (fO2) during deposition over a wide range. Upon increasing fO2 from 30 to 80 %, their hardness increases from 22 to 24 GPa and their indentation moduli increased from 380 to 410 GPa. The materials stayed single-phase crystalline with the rutile structure during vacuum annealing up to 1200 °C, only their orientation changed from random-like to highly 101-textured.

High-entropy alloys (HEAs), Reactive sputtering, Multi-element oxides

http://dx.doi.org/10.1016/j.vacuum.2019.108850