Magnetic and structural properties of L1-Mn50Ga50-xAlx epitaxially grown thin films

Epitaxially grown L10- MnGa(Al) continuous thin films with the c-axis along the film normal are successfully fabricated on MgO (001) substrates at a substrate deposition temperature Ts of around 400 °C. The order parameter S is found to decrease with Al content, except for that for Al = 0. The films under consideration exhibit the perpendicular magnetic anisotropy constant Ku of about 1 x 107 erg/cm3 at 300 K. In order to clarify the magnetic anisotropy mechanism, the correlation between Ms(T) and Ku(T) is discussed. It is found that the values of n in the power law relation Ku(T) ∼ Ms(T)n are found to be 2.6, 2.3, and 2.0 for the films of 2.5, 5.6, 11.2 Al at%, respectively. The present result suggests that the magnetic anisotropy of L10-MnGaAl thin films may be explained in terms of the two-ion model, where both the contributions of Mn and Ga are significant to the total magnetic anisotropy”. The decrease of the value n with Al addition n is of interest, but the reason for this change is not understood at present.