Magnetic τ-MnAlC thin film fabrication by high-vacuum thermal evaporation

•Magnetic τ-MnAlC thin films were fabricated by high-vacuum thermal evaporation.•High-concentration τ-MnAlC films were obtained by using a homogeneous τ-MnAlC and a heterogeneous ε-MnAlC-based alloy.•High-vacuum thermal deposition induced an island-type deposition of nanocrystalline τ-MnAlC grains.•The τ-MnAlC thin films presented a superparamagnetic-like state. Polycrystalline τ-MnAlC thin films were produced by thermal evaporation technique in one-step deposition and using as target materials a homogeneous τ-MnAlC(100%) and a heterogeneous ε-MnAlC(73.9%)/τ-MnAlC(22.0%)/Al6Mn(4.1%) alloy, both keeping the same atomic percent for each constituent element. X-ray diffraction patterns evidence all films present a high concentration of the desired τ-phase. A microscopy analysis shows the thermal evaporation induces an island-type deposition of nanocrystalline grains with an average size of 9 nm. A hysteresis loop shows the highest concentration τ-MnAlC film exhibits a superparamagnetic-like behavior, an extremely important nanomagnetic state for the development of actuators and magnetic field sensor.