Elemental analyzer

Total leaf carbon (C) and nitrogen (N) content were determined for the three plant species in July 2008, when Spartina seedlings were large enough to contain enough leaf tissue for these analyses. Three leaves per clone within each pot, and for each treatment, were collected and pooled for analysis. The samples were dried in an oven at 80 °C for 48 h, pulverized using a grinder (Cyclotech, Inc., Cypress, California, USA) and filtered using a screen of 80-µm. Total C and N concentration was determined for undigested samples with an elemental analyzer (Leco Instruments, Inc., Saint Joseph, Michigan, USA).

The magnetic material used to synthesize the composite was gas-atomized particles which composition was (Mn₅₇Al₄₃)₁₀₀C_1.19 (in the following, MnAlC), determined by inductively coupled plasma spectroscopy (ICP). The oxygen content in the alloy was 0.03 wt%, obtained by a LECO Elemental Analyzer. The particle shape was determined by scanning electron microscopy (SEM; Zeiss EVO HD159). SEM image in Figure 1(b) shows that the particles were quasi-spherical with an average diameter below 36 μm.
The crystallographic structure was determined by X-ray diffraction (XRD) using an X’Pert PRO Theta/2Theta diffractometer from Panalytical with Cu-K_α1 radiation (λ = 0.1541 nm). Figure 1(c) shows the XRD pattern of MnAlC particles revealing an ε-phase based crystallographic structure. A minor content of γ₂-phase is observed in the pattern as previously reported in other studies [18,20 (link)].
Annealing of the as-atomized powder was carried out at 650 °C in nitrogen atmosphere to allow for successful ε-to-τ phase transformation (Figure 1(c) and (e), respectively). Comparison of SEM images shows that there is no significant microstructural difference after annealing of the as-atomized particles (Figure 1(b) and (d)).

The soil used for measuring gravimetric water content was dried under 65 °C to constant weight, ground and analyzed for total C and N using elemental analysis (Leco Elemental analyzer).