Interface ferromagnetism in (110)-orientedLa0.7Sr0.3MnO3/SrTiO

Abstract

We explore manganite interface magnetism in epitaxially grown La 0.7 Sr 0.3 MnO 3 ͑LSMO͒ / SrTiO 3 ultrathin superlattices ͑SL͒ along ͑110͒ orientation. We show that robust ferromagnetism persists down to 4 monolayers ͑MLs͒ LSMO ͑ϳ1.1 nm in thickness͒, 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 B with an estimated interface moment of 3.2 B . In comparison to ͑100͒-oriented SLs which were previously shown to have a spin-canted ground state, ͑110͒oriented 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.

Increased Curie Temperature Induced by Orbital Ordering in La0.67Sr0.33MnO3/BaTiO3 Superlattices

“…This dead layer phenomenon may be related to electronic and/or chemical phase separation [9, 10], to growth characteristics and microstructure [11, 12], or to manganese e g orbital reconstruction [13, 14]. Recently, many efforts have been made to increase the T C of ultrathin perovskite manganite films by superlattice interface control and precise strain tuning [15–18]. Among the perovskite manganites, La 0.67 Sr 0.33 MnO 3 (LSMO) films have drawn increasing interest due to their colossal magnetoresistance effect, high T C , and half metallicity [19–23].…”

Atomic-scale engineering of ferroelectric-ferromagnetic interfaces of epitaxial perovskite films for functional properties

“…Unlike ordinary itinerant ferromagnets, the spin manganites are sensitive to the Mn-O-Mn bond and the local density of orbital states as both have orientational dependencies 6 . For in-plane (001) LSMO-BTO interface, while every MnO 6 octahedra has one TiO 6 octahedra as its neighbor, for (110) interface, every MnO 6 octahedra has two TiO 6 octahedra.…”

“…The larger the number of neighboring TiO 6 octahedra, higher is the expectation of localized electrons and stronger is the Mn-O-Mn double-exchange (DE) coupling, resulting in stronger magnetic moments. For (110) oriented LSMO, the lattice strain is less as compared to (001) oriented LSMO 6 leading to a smaller distortion of the MnO 6 octahedra and improved DE interactions. Investigations on interface magnetism have been done before by growing LSMO on (110) and on (001) oriented substrates.…”

Colossal anisotropic resistivity and oriented magnetic domains in strained La0.325Pr0.3Ca0.375MnO3 films

“…However, it would be highly desirable to have films with uniaxial in-plane strain with lower symmetry. This may be helpful, for instance, to select a certain orbital ordering 13 or a single-domain crystallographic structure, 15 or to obtain more favorable ferromagnetism and metallicity, 16 which are important for spintronic application. An uniaxial in-plane strain can be obtained by using orthorhombic substrates like NdGaO 3 (NGO).…”