Magnetic properties and thermal stability of Ti-doped CrO2 films

Abstract Chromium dioxide (CrO 2 ) is a striking half metal material which may have important applications in the field of spintronics. However, pure CrO 2 film is metastable at room temperature and the synthesis process can be only performed in a narrow temperature range of 390–410 °C with TiO 2 used as substrate material. Here, we report the preparation and investigation of (1 0 0) oriented Ti-doped CrO 2 films on TiO 2 substrates. It is found that Ti-doped films can maintain pure rutile phase even after a 510 °C post-annealing, showing much better thermal stability than pure CrO 2 films. Ti-doped films can be prepared in a wider temperature window (390–470 °C), which may be attributed to the improvement of thermal stability. The broadening of process window may be beneficial for further improvement of film quality by optimizing growth temperature in a larger range. In addition to the improvement of thermal stability, the magnetic properties of Ti-doped CrO 2 are also found to be tuned by Ti doping: saturation magnetizations of Ti-doped films at room temperature are significantly lower, and magnetic anisotropy decreases as the Ti-concentration increases, which is beneficial for decreasing switching current density in STT-based spintronic devices.