Effects of Oxygen Modification on the Structural and Magnetic Properties of Highly Epitaxial LaSrMnO (LSMO) thin films.

LaSrMnO, a strong semi-metallic ferromagnet having robust spin polarization and magnetic transition temperature (T) well above 300 K, has attracted significant attention as a possible candidate for a wide range of memory, spintronic, and multifunctional devices. Since varying the oxygen partial pressure during growth is likely to change the structural and other physical functionalities of LaSrMnO (LSMO) films, here we report detailed investigations on structure, along with magnetic behavior of LSMO films with same thickness (~30 nm) but synthesized at various oxygen partial pressures: 10, 30, 50, 100, 150, 200 and 250 mTorr. The observation of only (00 l) reflections without any secondary peaks in the XRD patterns confirms the high-quality synthesis of the above-mentioned films.

Surface Recombination in Ultra-Fast Carrier Dynamics of Perovskite Oxide LaSrMnO Thin Films.

Aspects of the optoelectronic performance of thin-film ferromagnetic materials are evaluated for application in ultrafast devices. Dynamics of photocarriers and their associated spin polarization are measured using transient reflectivity (TR) measurements in cross linear and circular polarization configurations for LaSrMnO films with a range of thicknesses. Three spin-related recombination mechanisms have been observed for thicker films (thickness of d ≥ 20 nm) at different time regimes (τ), which are attributed to the electron-phonon recombination (τ < 1 ps), phonon-assisted spin-lattice recombination (τ ∼ 100 ps), and thermal diffusion and radiative recombination (τ > 1 ns).

Observation and interpretation of negative remanent magnetization and inverted hysteresis loops in a thin film of LaSrMnO.

The observation of inverted magnetic hysteresis loops and negative magnetic remanence (NRM) in a 7.6 nm thin film of LaSrMnO grown on SrTiO substrates is reported. The film was grown employing pulsed laser deposition and characterized by reflection high-energy electron diffraction during growth and using x-ray reflectivity measurements post-growth.