Temperature-dependent out-of-plane anisotropy in compressively strained La_0.67Sr_0.33MnO₃ thin films

We studied the temperature and strain dependence of the perpendicular magnetic anisotropy in La_0.67Sr_0.33MnO₃ thin films by performing temperature- and angle-dependent magnetotransport measurements. Three films of similar thickness (14 u.c., 14 u.c. and 15 u.c.) but with different out-of-plane crystallographic strain (1.9%, 0.9% and -0.7%) are studied. The films are grown on LaAlO₃ and SrTiO₃ substrates by pulsed laser deposition. We observe a clear increase in the out-of-plane magnetic anisotropy with increasing out-of-plane strain in the angle-dependent magnetotransport measurements which is present up to 80 K for the highest (1.9%) strained sample. The deformation of the unit cell, as discussed in earlier reports, point to the magnetocrystalline anisotropy as the main driver altering the magnetic easy axis direction. Our results highlight the utility of the effective magnetocrystalline anisotropy as a tool to control the desired anisotropy in crystalline thin films of La_0.67Sr_0.33MnO₃.