Strain induced magnetic transition in CaMnO3 ultra thin films

AGUSTÍN LOPEZ PEDROSO; MARÍA ANDREA BARRAL; MÓNICA GRAF; ANA MARÍA LLOIS; M.H AGUIRRE; LAURA STEREN; SOLANGE DI NAPOLI

PHYSICAL REVIEW B

AMER PHYSICAL SOC

Lugar: New York; Año: 2020

1098-0121

The effect of high tensile strain and low dimensionality on the magnetic and electronic properties of CaMnO3 ultrathin films, epitaxially grown on SrTiO3 substrates, are experimentally studied and theoretically analyzed. By means of ab initio calculations, we find that, both, the high strain produced by the substrate and the presence of the free surface contribute to the stabilization of an inplane ferromagnetic coupling, giving rise to a non-zero net magnetic moment in the ultrathin films. Coupled with this change in the magnetic order we find an insulator-metal transition triggered by the quantum confinement and the tensile epitaxial strain. Accordingly, our magnetic measurements in 3nm ultrathin films show a ferromagnetic hysteresis loop, absent in the bulk compound due to its G-type antiferromagnetic structure.