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HoCrO3, a member of the rare-earth chromate family, is known to exhibit an orthorhombic structure with Pbnm space group in bulk at room temperature. We have employed the pressure driven powder consolidation technique, spark plasma sintering, for synthesizing HoCrO3 powder-compact, which exhibits a superior quality with fewer defects over that synthesized by conventional solid-state sintering (resulting in a large reduction of charge carrier mediated extrinsic dielectric contribution). The powder compact shows magneto-dielectric coupling but does not exhibit a detectable ferroelectric phase in the range of 50 K to 300 K. Low temperature Raman spectra show structural distortions below 250 cm−1, indicating Ho ion displacements. Temperature evolution of the crystal structure using synchrotron x-ray diffraction reveals a probable structural phase transition below 240 K. Pyrocurrent measurement, together with synchrotron x-ray diffraction analysis, further points to a magneto-structural transition at 100 K. [ABSTRACT FROM AUTHOR]

Total reflection X-ray fluorescence (TXRF) spectroscopy has seen remarkable progress over the past years. Numerous applications in basic and applied sciences prove its importance. The large spectral background, which is a major detrimental factor in the conventional X-ray fluorescence technique, limits the element detection sensitivities of the technique to the µg g-1 (ppm) range. This spectral background is reduced to a great extent in the TXRF technique due to the low extinction depth of the primary incident X-ray beam. In synchrotron radiation (SR) based TXRF measurements the spectral background is reduced further because of the polarization of the synchrotron X-ray beam. Here, we show in detail the influence of synchrotron polarization on the spectral background in a fluorescence spectrum and its significance towards TXRF detection sensitivities. We have performed TXRF measurements on standard reference materials to show that one obtains approximately one order of magnitude enhancement in the spectral signal strength by utilizing the anisotropic nature of the scattered synchrotron radiation in the horizontal detection geometry. [ABSTRACT FROM AUTHOR]