Magnetic properties and thermal stability of N-doped CrO2 (100) films

Abstract

Chromium dioxide (CrO2) is one of the perfect candidates for application in the field of spintronics due to its 100% spin polarization around the Fermi surface. In this work, N-doped epitaxial CrO2 (100) films were successfully synthesized on TiO2 substrates using the chemical vapor deposition technique in the nitrogen-involved atmosphere. The deposition window of N-doped CrO2 ranged from 300 to 430°C in contrast to narrow temperature window for CrO2 in pure O2 atmosphere. Compared with pure CrO2, N-doped films have better film quality, narrower orientation distribution and lower roughness. It was also found that the magnetic anisotropy and Curie temperature of the CrO2 film increased respectively with the N concentration, suggesting that N-doping offer an efficiently way for anisotropy manipulation. The annealing tests further reveal improved thermal stability of the N-doped film, N-doped films can withstand annealing temperatures as high as 470 °C in contrast to 420 °C for pure CrO2. The investigation on the electronic structure of N-doped CrO2 via first principle calculations suggests that N-doping only slightly affects the density of states of CrO2 without changing its half metallicity. Based on these results, N-doped CrO2 films may be promising for applications in spintronic devices.