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The magnetic dead layers in films a few nanometers thick are investigated for La0.7Sr0.3MnO3 on SrTiO3(STO), LaAlO3(LAO), and (LaAlO3)0.3(Sr2TaAlO6)0.7 (LSAT) substrates. An anomalous moment found to persist above the Curie temperature of the La0.7Sr0.3MnO3 films is not attributed to the films, but to oxygen vacancies at or near the surface of the substrate. The contribution to the moment from the substrate is as high as 20~\mu \mathrm {{B}} /nm2 in the case of STO or LSAT. The effect is increased by adding an STO cap layer. Taking this d-zero magnetism into account, extrapolated magnetic dead-layer thicknesses of 0.8, 1.5, and 3 nm are found for the manganite films grown on LSAT, STO, and LAO substrates, respectively. An STO cap layer eliminates the LSMO dead layer. [ABSTRACT FROM AUTHOR]

The effect of vacuum annealing thin films of the compensated ferrimagnetic half-metal Mn2RuxGa at temperatures from 250 °C to 400 °C is investigated. The 39.3 nm films deposited on (100) MgO substrates exhibit perpendicular magnetic anisotropy due to a small ~ 1% tetragonal elongation induced by the substrate strain. The main change on annealing is a modification in the compensation temperature T\text {comp} , which first increases from 50 K for the as-deposited film to 185 K after annealing at 250 °C, and then falls to 140 K after annealing at 400 °C. There are minor changes in the atomic order, coercivity, resistivity, and anomalous Hall effect (AHE), but the net magnetization measured by SQUID magnetometry with the field applied in-plane or perpendicular-to-the-plane changes more significantly. It saturates at 20 –30 kA \cdot ~\textm^-1 at room temperature, and a small soft component is seen in the perpendicular SQUID loops, which is absent in the square AHE hysteresis loops. This is explained by the half-metallic nature of the compound; the AHE probes only the 4c Mn sublattice that provides the spin-polarized electrons at the Fermi level, whereas the SQUID measures the sum of the oppositely aligned 4c and 4a sublattice magnetizations. [ABSTRACT FROM AUTHOR]