Strain-modulated structure distortion and magnetic properties of orthorhombic LuMnO3 thin films

Epitaxial orthorhombic LuMnO3 (LMO) films were deposited on (001)-LaAlO3 substrates by pulsed laser deposition. The in-plane compressive strain in the films was induced by the mismatch between LMO film and substrate. The results of X-ray diffraction and Raman spectra show that the lengths of in-plane Mn-O bonds stretching was suppressed and MnO6 distortion was varied by the compressive strain. The magnetic studies reveal that ferromagnetic (FM) and antiferromagnetic (AFM) phases coexist in the films. The AFM ordering was weakened with decreasing thickness of the films, and FM appears in the thin film. Considering the distribution of strain in films, FM phase may exist in the thin layer in the interface under in-plane compressive strain, while AFM structure is stable in the region near the surface with strain relaxed. The FM ordering is induced by the uniform d3z2_r2 type orbital order under compressive strain. These results show that the magnetic states of LMO films can be sensitively manipulated by the strain.

Automated summary

Epitaxial orthorhombic LuMnO3 films with in-plane compressive strain were deposited on (001)-LaAlO3 substrates by pulsed laser deposition. The strain-induced change in MnO6 distortion and in-plane Mn-O bond lengths suppressed the antiferromagnetic ordering and induced ferromagnetic ordering. The magnetic states of the films can be sensitively manipulated by tuning the thickness and strain distribution.