Capabilities of highly sensitive surface-enhanced infrared absorption (SEIRA) spectroscopy are demonstrated by exploiting large-area templates (cm 2 ) based on selforganized (SO) nanorod antennas. We engineered highly dense arrays of gold nanorod antennas featuring polarization-sensitive localized plasmon resonances, tunable over a broadband near-and mid-infrared (IR) spectrum, in overlap with the so-called "functional group" window. We demonstrate polarization-sensitive SEIRA activity, homogeneous over macroscopic areas and stable in time, by exploiting prototype self-assembled monolayers of IR-active octadecanthiol (ODT) molecules. The strong coupling between the plasmonic excitation and molecular stretching modes gives rise to characteristic Fano resonances in SEIRA. The SO engineering of the active hotspots in the arrays allows us to achieve signal amplitude improved up to 5.7%. This figure is competitive to the response of lithographic nanoantennas and is stable when the optical excitation spot varies from the micro-to macroscale, thus enabling highly sensitive SEIRA spectroscopy with costeffective nanosensor devices.

We demonstrate the capability of single plasmonically active nanoslits for sensing of small fine dust particles via surface-enhanced infrared absorption (SEIRA) spectroscopy. Investigating phononic excitations of individual spherical silica particles coupled to the plasmonic excitation of single nanoslits, we are able to detect and chemically identify single spheres with diameters of 240 nm by their enhanced phononic signal. The single silica spheres in nanoslits lead to Fano-type phononic signals on the plasmonic background. The enhancement of the phononic silica signal is highest for particles located in the middle of the slit, in accordance with the FDTDsimulated near-field distribution along the slit at resonance. Our results reveal, that resonant plasmonic nanoslits are promising substrates for SEIRA spectroscopy of fine and ultra fine dust particles and guide the way toward SEIRA based dust sensing devices.

Four new manganese germanates and silicates, AMnGeO (A = Li, Na) and AMnSiO (A = Na, Ag), were prepared, and their crystal structures were determined using the X-ray Rietveld method. All of them contain all components in tetrahedral coordination. LiMnGeO is orthorhombic (Pmn2) layered, isostructural with LiCdGeO, and the three other compounds are monoclinic (Pn) cristobalite-related frameworks. As in other stuffed cristobalites of various symmetry (Pn AMXO, Pna2 and Pbca AMO), average bond angles on bridging oxygens (here, Mn-O-X) increase with increasing A/X and/or A/M radius ratios, indicating the trend to the ideal cubic (Fd3̅m) structure typified by CsAlO. The sublattices of the magnetic Mn ions in both structure types under study (Pmn2 and Pn) are essentially the same; namely, they are pseudocubic eutaxy with 12 nearest neighbors. The magnetic properties of the four new phases plus LiMnSiO were characterized by carrying out magnetic susceptibility, specific heat, magnetization, and electron spin resonance measurements and also by performing energy-mapping analysis to evaluate their spin exchange constants. AgMnSiO remains paramagnetic down to 2 K, but AMnXO (A = Li, Na; X = Si, Ge) undergo a three-dimensional antiferromagnetic ordering. All five phases exhibit short-range AFM ordering correlations, hence showing them to be low-dimensional magnets and a magnetic field induced spin-reorientation transition at T < T for all AFM phases. We constructed the magnetic phase diagrams for AMnXO (A = Li, Na; X = Si, Ge) on the basis of the thermodynamic data in magnetic fields up to 9 T. The magnetic properties of all five phases experimentally determined are well explained by their spin exchange constants evaluated by performing energy-mapping analysis.