Ferromagnetic resonance in strained and relaxed regions of (La,Na)MnO3/LaAlO3 (001) films

Structural and resonant properties of 750-nm-thick (La,Na)MnO3 films grown by magnetron sputtering on LaAlO3 (001) single crystalline substrates have been studied. The magnetic resonance studies reveal that the low-temperature state of the films is characterized by the coexistence of two types of ferromagnetic regions with different magnetizations. The comprehensive analysis of the X-ray and magnetic resonance data makes it possible to conclude that structural and magnetic heterogeneity originates from differently strained regions, which were formed during the films growth.