(a) HRTEM images of LSMO nanoparticles covered with PPy. (b) Enhanced detail evidencing the core-shell structure resulted by PPy attachment. The atomic planes corresponding to the (100) family of LSMO can be seen in (b).
TEM image of an ensemble of LSMO nanoparticles covered with PPy. Spherical bundles wrapped within a polymeric “cloud” can be observed in certain cases.
(Color online) XPS recorded spectrum of Mn 2 p core-level doublet of the LSMO@PPy 1 sample together with corresponding deconvolutions and fitted curves. Peaks labeled A and B correspond to Mn3+and Mn4+, respectively. Two shake-up satellites are also present in the spectrum.
(Color online) The magnetization curves vs applied magnetic field at room temperature of the LSMO@PPy samples 1-3 and bare LSMO nanoparticle samples. The absolute magnetizations are calculated referred to the LSMO content of each specific sample. The continuous lines represent the best fits obtained for each sample using Eq. (1).
(Color online) Magnetization vs temperature dependences under ZFC-FC conditions for LSMO and LSMO@PPy 1 – 3 nanocomposites. The applied magnetic field was 0.01 T.
(Color online) Temperature dependences of mean energy barrier heights for the LSMO sample together with the LSMO@PPy samples 1 – 3. The inset shows the energy barriers distributions of mentioned samples as resulted from first derivative of TRM.
(Color online) Temperature dependences of the coercive field H C for samples 1 – 3 together with LSMO sample.
(Color online) X-ray absorption near edge structure (XANES) spectra at the Mn K-edge for LSMO nanoparticles and LSMO@PPy samples 1 – 3. The inset presents the first derivative spectra for the same samples showing significant modifications of the pre-edge features (below 6550 eV) with increasing polymer concentrations. The vertical line indicates the position of the main transition of Mn K-edge.
(Color online) Deconvolution of pre-edge lines for LSMO@PPy sample 1. The deconvolution was made by using a modified Voigt profile while the baseline was set by considering spline functions.
(Color online) Mn-K pre-edge features for the LSMO@PPy samples and for LSMO uncoated nanoparticles after the extraction of the base lines. A1 transitions involves majority partially filled eg states while A2 feature is associated to minority upper empty eg states. The higher energy feature labeled the B is associated with Mn-4p states.
Initial synthesis conditions for LSMO@PPy samples and weight contents as resulted from XPS analysis.
The calculated values of weight contents of the samples as resulted from XPS data. The last column contains the number of Bohr magnetons per formula unit, μ s calculated from M S.
The line positions and integral intensities for A1, A2 and B components.
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