(a) The schematic lattice structure of the N = 2 superlattice; brown dot (La), green dot (Sr), purple dot (Mn), gray dot (Ti), red dot (O); 1 s.c. means 1 supercell. (b) Hysteresis loops of the N = 8 (red), 2 (green), and 1 (blue) superlattices and the LaMnO3 thin film (black) measured at 10 K.
(a)-(c) Hysteresis loops of the N = 8, 2, and 1 superlattices measured at 10 K (yellow cross), 50 K (light blue square), 100 K (pink dot) and the corresponding Brillouin function fits (dashed lines). (d) The retrieved molecular field constant λ as a function of temperature.
(a) The M vs T curves after ZFC and FC of the N = 8 superlattice and the LaMnO3 thin film. (b) The N = 1 and N = 2 superlattices. All measurements were done in an applied field of 0.005 T. (c) Tonset f, Tonset, Tc, and Tb of all superlattices and the reference thin film. The inset of (b) is a Langevin function fit to the N = 2 superlattice.
The M/M(0) vs T/Tc curves measured after FC of the N = 8, 2 superlattices and the LaMnO3 thin film. The S = 2 Brillouin function fit to the N = 8 superlattice is indicated by the green dashed line. The measuring field is zero for the N = 8 superlattice and 0.005 T for the other two samples.
(a) The ρ/T vs 1/T plots of the superlattices and the reference thin film measured above the ferromagnetic transition temperatures. (b) The small polaron activation energy Δ vs Ms (left axis) and Δ vs Mn3 + concentration (right axis). The Mn3+ concentration is predicted using its linear relationship with Δ in Ref. 26 . The associated errors are from the Δ value fitting using the small-polaron-hopping model.
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