The present study aims to provide new insights into the temperature-dependent spectral variations in the near infrared (NIR) region of the spectrum of water by comparing chemometrics with spectroscopic analysis. Fourier transform (FT)-NIR spectra of water in the 9000–5500 cm−1 region have been measured over a temperature range of 5–85°C. The observed spectral changes have been analysed by both chemometrics, such as multilinear regression (MLR), principal component regression (PCR) and partial least squares (PLS) regression, and spectroscopic data analyses, such as second derivative, difference spectra and curve fitting. The second derivative of the NIR spectra of water suggests that an intense feature around 6900 cm−1, due to the combination of antisymmetric and symmetric stretching modes of water, consists of at least five component spectra. Each component spectrum may be ascribed to the water species with no, one, two, three and four hydrogen bonds. Curve fitting has been performed for the 6900 cm−1 band and it has been found that the species with no hydrogen bonds increase largely with temperature, while those with more than two hydrogen bonds decrease. The temperature of water has been predicted by use of MLR, PCR and PLS regression. PCR and PLS regression loadings plots for Factor 1 of the models for the prediction of the temperature of water are almost identical with the difference spectrum of water between 5 and 85°C; both the loadings plots and the difference spectrum reflect strongly the changes in the hydrogen bonds of water. Loadings plots of Factor 1 of the PCR and PLS regression models are very similar to each other. It is very likely that since the temperature-dependent spectral variations of water in the NIR region are very regular, and the spectra have only very small noise and baseline changes, PCR and PLS regression select nearly identical factors.

Material dependence of the anomalous Nernst effect (ANE) in perpendicularly magnetized ordered-alloy thin films is systematically investigated. The ANE was found to have a tendency to increase simply as uniaxial magnetic anisotropy increased at room temperature. The ANE increases as temperature increases from 10 to 300 K for all the materials. However, the signs of the ANE in Fe-based ordered-alloys (L10-FePt and L10-FePd) and in a Co/Ni multilayer are opposite to those in Mn-based ordered-alloys (L10-MnGa and D022-Mn2Ga). Ordered-alloys with larger uniaxial magnetic anisotropies reveal larger ANE and might be desirable for thermoelectric applications.

We prepared L10-ordered FeNi alloy films by alternate deposition of Fe and Ni monatomic layers, and investigated their magnetic anisotropy. We employed a non-ferromagnetic Au-Cu-Ni buffer layer with a flat surface and good lattice matching to L10-FeNi. An L10-FeNi film grown on Au6Cu51Ni43 showed a large uniaxial magnetic anisotropy energy (Ku = 7.0 × 10(6) erg cm(-)3). Ku monotonically increased with the long-range order parameter (S) of the L10 phase. We investigated the Fe-Ni composition dependence by alternating the deposition of Fe 1 − x and Ni 1 + x monatomic layers (− 0.4 < x < 0.4). Saturation magnetization (Ms) and Ku showed maxima (Ms = 1470 emu cm(-3), Ku = 9.3 × 10(6) erg cm(-3)) for Fe60Ni40 (x = -0.2) while S showed a maximum at the stoichiometric composition (x = 0). The change in the ratio of lattice parameters (c/a) was small for all compositions. We found that enrichment of Fe is very effective to enhance Ku. The large Ms and Ku of Fe60Ni40 indicate that Fe-rich L10-FeNi is promising as a rare-earth-free permanent magnet.

Heusler alloys are well known in other fields but little known in catalysis, where we demonstrate that they have great potential.

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