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The ternary transition metal boride Fe2AlB2 is a unique ferromagnetic "MAB" phase that demonstrates a sizable magnetocaloric effect near room temperature—a feature that renders this material suitable for magnetic heat pump devices (MHP), a promising alternative to conventional vapor compression technology. Here, we provide a comprehensive review of the material properties of Fe2AlB2 (magnetofunctional response, transport properties, and mechanical stability) and discuss alloy synthesis from the perspective of shaping these materials as porous active magnetic regenerators in MHPs. Salient aspects of the coupled magnetic and structural phase transitions are critically assessed to elucidate the fundamental origin of the functional response. The goal is to provide insight into strategies to tune the magnetofunctional response via elemental substitution and microstructure optimization. Finally, outstanding challenges that reduce the commercial viability of Fe2AlB2 are discussed, and opportunities for further developments in this field are identified. [ABSTRACT FROM AUTHOR]

Predominantly single-phase AlFe2B2 powders were synthesized by a molten salt sintered/sintering (MS3) method wherein a green compact comprising of Al, Fe and B powders encapsulated in a KBr salt was heat treated at 1000°C for 12 h in open air. Results reveal that the magnetofunctional properties of AlFe2B2 powders synthesized via the novel MS3 method is comparable to that of powders produced via melt-based or powder metallurgy methods that have been previously reported in the literature. Since no inert environment or post-fabrication annealing or acid treatments is required, it is construed that the MS3 processing scheme is the most cost-effective and energy-efficient method to synthesize AlFe2B2 powders to date. [ABSTRACT FROM AUTHOR]

In this work, we demonstrate that the magnetocaloric response of FeRh-based compounds may be tailored for potential magnetic refrigeration applications by chemical modification of the FeRh lattice. Alloys of composition Fe(Rh1-xAx) or (Fe1-xBx)Rh (A=Cu, Pd; B=Ni; 0

Millimeter wave transmittance measurements have been successfully performed on commercial samples of micro- and nano-sized particles of BaFe12O19 and SrFe12O19 hexaferrite powders and nano-sized particles of BaFeO2 and SrFeO2powders. Broadband millimeter wave transmittance measurements have been performed using free space quasi-optical spectrometer, equipped with a set of high power backward wave oscillators covering the frequency range of 30 - 120 GHz. Real and imaginary parts of dielectric permittivity for both types of micro- and nanoferrites have been calculated using analysis of recorded high precision transmittance spectra. Frequency dependences of magnetic permeability of ferrite powders, as well as saturation magnetization and anisotropy field have been determined based on Schlöemann's theory for partially magnetized ferrites. Micro- and nano-sized ferrite powders have been further investigated by DC magnetization to assess magnetic behavior and compare with millimeter wave data. Consistency of saturation magnetization determined independently by both millimeter wave absorption and DC magnetization have been found for all ferrite powders. These materials seem to be quite promising as tunable millimeter wave absorbers and filters, based on their size-dependent absorption. [ABSTRACT FROM AUTHOR]

The article presents a study on determining volatile organic compounds in biological samples through the use of headspace solid-phase microextraction and gas chromatography (GC) applied to toluene and styrene toxic compounds in the samples. These compounds are said to lead the impairment of the nervous system and this notion is validated through an examination conducted to the biological compound samples. Liquid-liquid phase method, headspace (HS) method, and solid-phase microextraction (SPME) methods are utilized in the samples. Results show that the HS-SPME-GC method can be applied to the estimation of styrene and toluene in small volumes of biological fluids.

We report on the multicaloric response of the Fe49 Rh51 alloy under the combined application of hydrostatic pressure and magnetic field. Experimental data are complemented by a mean field model that takes into account the interplay between structural and magnetic degrees of freedom. A large multicaloric strength has been found for this alloy, and it is shown that a suitable combination of pressure and magnetic field enables the sign of the entropy change to be reversed and thus the multicaloric effect can be tuned from conventional to inverse. It is also shown that an extended temperature window for the multicaloric effect can be achieved by taking advantage of the coupling between structure and magnetism which enables a cross response of the alloy under the application of different external fields. Mean field calculations remarkably reproduce experimental results. [ABSTRACT FROM AUTHOR]

We report, for the first time, correlations between crystal structure, microstructure and magnetofunctional response in directionally solidified [110]-textured Fe 83 Ga 17 Er x (0 < x < 1.2) alloys. The morphology of the doped samples consists of columnar grains, mainly composed of a matrix phase and precipitates of a secondary phase deposited along the grain boundary region. An enhancement of more than ~275% from ~45 to 170 ppm is observed in the saturation magnetostriction value ( &lambda; s ) of Fe 83 Ga 17 Er x alloys with the introduction of small amounts of Er. Moreover, it was noted that the low field derivative of magnetostriction with respect to an applied magnetic field ( i.e.,&nbsp;d&lambda;s/dHapp for H app up to 1000 Oe) increases by ~230% with Er doping (d&lambda;s/dHapp,FeGa= 0.045 ppm/Oe; d&lambda;s/dHapp,FeGaEr= 0.15 ppm/Oe). The enhanced magnetostrictive response of the Fe 83 Ga 17 Er x alloys is ascribed to an amalgamation of microstructural and electronic factors, namely: (i) improved grain orientation and local strain effects due to deposition of Er in the intergranular region; and (ii) strong local magnetocrystalline anisotropy, due to the highly anisotropic localized nature of the 4f electronic charge distribution of the Er atom. Overall, this work provides guidelines for further improving galfenol-based materials systems for diverse applications in the power and energy sector.