Theoretical stability, thin film synthesis and transport properties of the Mo_{<i>n</i> +1}GaC<i>_n</i> MAX phase

Abstract

The phase stability of Mo n +1 GaC n has been investigated using ab‐initio calculations. The results indicate stability for the Mo 2 GaC phase only, with a formation enthalpy of –0.4 meV per atom. Subsequent thin film synthesis of Mo 2 GaC was performed through magnetron sputtering from elemental targets onto Al 2 O 3 [0001], 6H‐SiC [0001] and MgO [111] substrates within the temperature range of 500 °C and 750 °C. High structural quality films were obtained for synthesis on MgO [111] substrates at 590 ºC. Evaluation of transport properties showed a superconducting behavior with a critical temperature of approximately 7 K, reducing upon the application of an external magnetic field. The results point towards the first superconducting MAX phase in thin film form. (© 2015 WILEY‐VCH Verlag GmbH &amp;Co. KGaA, Weinheim)