Transition metal nitrides with ferrimagnetism have recently attracted attention because of their skyrmionic functionalities at room temperature 1,2, and the topological Hall effect (THE) was observed for Mn based transition metal nitrides such as Mn4N thin films 3,4. The conventional spin texture for the film is collinear with perpendicular magnetic anistoropy, which is remarkably sensitive to the growing temperature as well as substrate-induced strain 5,6. Therefore, these characterisitcs of the Mn4N warrants further study how the spin texture is modulated by the method of elemental doping, and it is our expectation that the turnability of spin textures of the films could allow us to realize possible skyrmionic devices that work under no external magnetic field. In this study, we investigated the THE for the sputter-deposited (111)- and (110)-oriented Mn4(N,B) films aiming the control of topological spin textures by elemental-doping of B 7.
Figures 1 shows the representative THE for the 111-oriented Mn4N film without B at 300K. The THE component was extracted from the total AHE component, suggesting the presence of non-coplanar spin texture for the films at room temperature. Figure 2 shows the measurement temperature (T) dependence of ρxyTHE/ρxyAHE ratio for the films with and without B. The ratio increased at lower T, suggesting the stabilization of non-coplanar spin textrue at lower T. In addition, supression of THE was observed by B for all T. These results show a dilution effect in the spin frustration state with topological spin texture by B. Conversely, slight increase of THE was observed by B in the case of 110-oriented films. Therefore, B in the antiperovskite systems such as Mn4N could acts as an efficient suppressor or booster of frustrated exchange interactions between Mn atoms.
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