Interface ferromagnetism in (110)-oriented<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:msub><mml:mrow><mml:mtext>La</mml:mtext></mml:mrow><mml:mrow><mml:mn>0.7</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>Sr</mml:mtext></mml:mrow><mml:mrow><mml:mn>0.3</mml:mn></mml:mrow></mml:msub><mml:msub><mml:mrow><mml:mtext>MnO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mrow><mml:mtext>SrTiO</mml:mtext></mml:mrow><mml:mn>3</mml:mn></mml:msub></mml:mrow></mml:math>ultrathin superlattices

We explore manganite interface magnetism in epitaxially grown ${\text{La}}_{0.7}{\text{Sr}}_{0.3}{\text{MnO}}_{3}(\text{LSMO})/{\text{SrTiO}}_{3}$ ultrathin superlattices (SL) along (110) orientation. We show that robust ferromagnetism persists down to 4 monolayers (MLs) LSMO ($\ensuremath{\sim}1.1\text{ }\text{nm}$ in thickness), of which 50% Mn is at the interface state. Above 8 MLs, the magnetic moment is nearly saturated to the theoretical value of $3.7{\ensuremath{\mu}}_{\text{B}}$ with an estimated interface moment of $3.2{\ensuremath{\mu}}_{\text{B}}$. In comparison to (100)-oriented SLs which were previously shown to have a spin-canted ground state, (110)-oriented SLs exhibit stronger low-dimensional ferromagnetism and better metallicity, suggesting a ferromagnetic-interface spin state well suited for all-oxide spintronic devices. The underlining mechanism is qualitatively discussed.