Ultra-low magnetic damping of perovskite La0.7Sr0.3MnO3 thin films

The perovskite La0.7Sr0.3MnO3 (LSMO) films grown on different substrates were investigated by an angle resolved broadband ferromagnetic resonance technique. All films exhibited a four-fold magnetocrystalline anisotropy, which is in accord with the crystal structure. Moreover, a perpendicular uniaxial anisotropy changed from the (001)pc easy plane to the [001]pc easy direction when the strain of LSMO films varies from tensile to compressive. The ultra-low magnetic damping constant of 5.2 × 10−4 was obtained for a 44.6 nm LSMO film on an NdGaO3 (110) substrate. The breathing Fermi surface model in which the damping constant is proportional to the density of states at Fermi energy is the dominant mechanism for the intrinsic magnetic relaxation.