Magnetic order in epitaxial (La2/3Sr1/3MnO3)3/(BaTiO3)3 trilayer heterostructures: Evidence for quasi-two-dimensional ferrimagnetism
The realization of artificial magnetic structures with high epitaxial quality and elevated critical temperatures remains a key challenge for spintronics. Here, we report the fabrication and characterization of epitaxial (La2/3Sr1/3MnO3)3/(BaTiO3)3 trilayer heterostructures grown by layer-by-layer laser ablation. High-resolution transmission electron microscopy, magnetization measurements, and neutron diffraction confirm their exceptional crystalline order and the absence of structural defects. Neutron diffraction reveals no antiferromagnetic Bragg peaks, ruling out most antiferromagnetic configurations with a non zero wave vector Q. Magnetic hysteresis loops instead evidence a ferromagnetic order with a remanent moment of about 0.5 bohr magneton per Mn atom at room temperature, persisting either in-plane or out-of-plane depending on the applied field. Our findings highlight neutron diffraction as a powerful tool for elucidating the magnetic structure of complex thin films and suggest that weak interlayer coupling through BaTiO3 leads to ferromagnetism with a high critical temperature (about 600 K).