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In this paper, CoRuFeX (X = Si, Ge) alloys were investigated by means of x-ray diffraction, Mössbauer spectroscopy, magnetic and magneto-transport measurements. Alloys are found to be exist in Y-type structure with presence of some B2 disorder. High values of Curie temperature ( T C ) of 867 K and 833 K are obtained for CoRuFeSi and CoRuFeGe alloys, respectively. The obtained T C values are found to be highest among all the equiatomic quaternary Heusler alloys. The saturation magnetization ( M S ) values are found to be in good agreement with the values obtained from Slater-Pauling estimation, which is a prerequisite for half-metallic ferromagnets. Electrical resistivity in the temperature range of 5–300 K gives an indirect evidence of half-metallic behavior in these alloys at low temperatures. Considering high T C and the transport behavior, both these materials seem to be interesting for spintronic applications. [ABSTRACT FROM AUTHOR]

The effect of partial substitution (50%) of Si by other sp-valent elements such as Al, Ga, Ge, In and Sn on structure, magnetic properties and electrical resistivity of full Heusler type Co 2 FeSi alloys was investigated. The results revealed that these alloys (except Sn substituted alloy) consist of mostly L2 1 ordered phase along with some B2 type disordered phase. The highest L2 1 ordering was seen in Co 2 FeSi 0.5 Ge 0.5 alloy. The magnetization studies showed all alloys obey the Slater–Pauling rule at 4 K except for Sn substituted alloy. However, at room temperature, only Ga, Ge and Al substituted alloys followed the Slater–Pauling rule. Electrical transport studies revealed the presence of half-metallic behavior at low temperatures in all alloys. However, half-metallicity was preserved to some extent at room temperature only in Ga and Ge substituted Co 2 FeSi alloys. [ABSTRACT FROM AUTHOR]

Abstract: The effect of Fe and rare-earths (Tb&Dy) addition on the martensitic transformation, magnetic and mechanical properties of the Ni50Mn30Ga20 (at%) ferromagnetic shape memory alloy was investigated. The results show that the rare-earths exhibit negligible solubility in the Ni–Mn–Ga–Fe matrix phase and formed grain boundary phase. The grain boundary precipitate enhances the compressive ductility of the alloys. The martensite transformation temperature was found to be increased by the addition of rare-earths, while, Fe increased the Curie temperature of the Ni–Mn–Ga alloy. However, with increase in Fe content, an additional (Ni,Fe)3(MnGa) precipitate is formed, leading to decrease in martensite transformation temperature and compressive ductility. [ABSTRACT FROM AUTHOR]

Abstract: Crystal structure of the phases, microstructure and magnetocaloric effect were investigated in Gd5Si2(Ge1−x Ga x )2 alloys with x =0, 0.01, 0.02 and 0.03. The phase identification and compositional analysis were carried out by a combination of X-ray diffraction, scanning electron microscopy and electron probe micro-analysis. The Gd5Si2Ge2-type matrix phase having an orthorhombic structure co-exists with Gd5Ge3-type and GdGe-rich phases. Ga was found to have preferentially partitioned to the orthorhombic Gd5Si2Ge2-type matrix phase. Magneto-structural transition temperatures determined from differential scanning calorimetry and thermo-magnetic techniques revealed that Ga substituted alloys exhibit only magnetic transition unlike parent Gd5Si2Ge2 alloy which displays both structural and magnetic transitions. A maximum magnetic entropy change (ΔS)M of 7.0J/kgK was obtained in x =0 alloy for a magnetic field change of 2T and its magnitude was lower in the Ga substituted alloys. [Copyright &y& Elsevier]

Abstract: Ni-rich ferromagnetic Ni–Mn–Ga Heusler alloys were investigated for structural and magneto-caloric effect. The structural transition from austenite to martensite near room temperature was observed with the increase of Ni content. The saturation magnetization measured at room temperature decreased with the increase of Ni content. A large change in magnetization (32%) was observed even for a small increase in Ni concentration (12%). The martensitic transition temperature (T M) and Curie temperature (T C) of all the samples were studied using thermo-magnetic as well as differential scanning calorimetry (DSC) techniques. The martensite and the magnetic transitions were found to be sensitive to the composition and were tuned through alloy composition to occur simultaneously at near room temperature. A change in magnetic entropy, (ΔS)M of −0.68J/kgK was determined in Ni55Mn20Ga25 for which T M and T C were close to room temperature. [Copyright &y& Elsevier]

The electrochemical performance of ternary metal oxide electrodes exhibiting faradic battery-type characteristics, represents a promising and desirable solution for addressing the ongoing energy crisis. In the current investigation, we present the optimized solution-combustion synthesis of Co 0.03 Ni 0.97 Fe γ Mn 2-γ O 4 nanoparticles, with varying Fe concentrations (γ=0.01, 0.05, 0.10 %), specifically tailored for application in supercapacitors. The Styrofoam-natured (CNMFO:1) exhibited outstanding specific capacitance, reaching 489.12 Fg−1 at a scan rate of 50 mVs−1. Moreover, validation through galvanostatic charge-discharge (GCD) investigations substantiated a notable specific capacitance of 391.41 Fg−1, achieved at a current density of 1Ag−1. In addition, the CNMFO:1 electrode demonstrated remarkable cyclic stability, retaining 83.87 % of its initial performance over 6000 cycles. Similarly, the fabricated asymmetric device of (CNMFO:1||AC) also demonstrated a maximum specific capacitance of 33.86 Fg−1 under a current density of 1Ag−1, which exhibits good energy and power density of 10.52 Wh Kg−1 and 749.34 W Kg−1 respectively. From the overall observation, the CNMFO:1 electrode exhibited notable cyclic stability and electrochemical reversibility. This research recommends that CNMFO:1 nanocomposite have an extraordinary potential for evolution of active electrode materials forthcoming supercapacitors in energy storage system. • Synthesis: Co 0.03 Ni 0.97 Mn 2-γ O 4 (γ=Fe:0.01, 0.05, 0.10 %) nanoparticle using solution-combustion route. • Characterization confirms the successful formation of the Styrofoam natured of the CNMFO:1 electrode. • The prepared CNMFO:1 electrode exhibits an excellent specific capacitance of 489.12 Fg−1 at 50 mV−1. • The CNMFO:1 electrode showcased prolonged cyclic stability. • The developed ASC device delivers an impressive energy and power density of 10.52 Wh Kg−1 and 749.34 W Kg−1 [ABSTRACT FROM AUTHOR]

Abstract: Ferroelectromagnetic, La2Bi7Fe5Ti3O27 compound was synthesized using a solid-state reaction technique. Basic crystal data of the compound were obtained by XRD. Detailed studies of electrical properties (i.e., dielectric and impedance) of the material carried out in wide frequency (102 to 106 Hz) and temperatures (30 to 500°C) ranges showed that these properties are strongly dependent on frequency and temperature. Magnetic measurements of the material provided a remanent magnetization of 0.011emu/g at room temperature. [Copyright &y& Elsevier]

Solid polymer electrolytes (SPEs) in lithium-ion batteries (LIBs) are emerging as promising alternative for liquid electrolytes. However, one of the drawbacks of SPEs is incompatibility between lithium metal anode / electrolyte that leads to the low ionic conductivity and lower cycling performance of LIBs. The present study show that fabrication of free-standing flexible hybrid solid polymer electrolyte (HSPE) based on poly(vinylidene fluoride- co -hexafluoro propylene)/poly(vinyl acetate) polymer blend electrolyte with TiO 2 nano-ceramic filler (NCF). The incorporation of TiO 2 -NCF aids in simultaneous improvements of the ionic conductivity and mechanical properties of host matrix. HSPE with 7.5 wt% TiO 2 exhibits highest ionic conductivity of 2.69 × 10−3 S cm−1 at 30 °C, which is ~2.5 time higher than ceramic free HSPE. In addition, the incorporation of TiO 2 enhances the high thermal stability (thermal degradation at 350 °C) and mechanical strength (stress 8.4 MPa) of the HSPE. Remarkably, HSPE with 7.5 wt% TiO 2 -NCF possess large Li+ transference number (0.53) with extended electrochemical stability window (5.4 V) and superior compatibility with lithium metal which is highly desirable for high voltage LIBs. The Li/HSPE/LiFePO 4 cell showed superior charge discharge properties, cycling stability and rate capability. Suppression of growth and proliferation of Li dendrites was demonstrated by time dependent impendence analysis. Furthermore, density functional theory (DFT) calculations confirm the mutual interactions between TFSI− and ions in electrolytes and that between TiO 2 segments and polymer segments. This work exemplifies the significant role of TiO 2 -NCF in enhanced electrochemical performance of polymer based free standing flexible HSPE. • Hybrid solid polymer electrolyte (HSPE) fabricated using TiO 2 nano-ceramic filler (NCF). • P(VdF- co -HFP)-PVAc-EC-LiTFSI with NCF show enhanced ionic conductivity and flexibility. • The use of HSPE has effectively suppressed the growth of Li-dendrites, with high Li t +. • DFT calculations confirms interaction of NCF with ions in electrolytes and polymer. [ABSTRACT FROM AUTHOR]

Highlights: [•] The pressure effects on ΔS M were investigated in Si doped Ni–Mn–Sn alloys. [•] The T m and Curie temperature of the austenitic phase changes with pressure. [•] The maximum ΔS M of 24.5Jkg−1 K−1 at 9.7kbar were observed for x =1 alloy. [•] The RC increases for x =1 alloy and can be used for magnetic refrigeration. [ABSTRACT FROM AUTHOR]

Highlights: [•] Complete amorphous phase is obtained in as spun ribbons upto 25at.% Si alloy. [•] 18% Si alloy exhibits highest glass forming ability as it is at eutectic point. [•] Annealing of all ribbons yields the precipitation of Nanocrystalline Fe3Si phase. [•] Si in Fe3Si phase increases from 21 to 25at.% for 11 to 25at.% Si alloys. [•] Coercivity decreases with Si content upto 18% Si and then increases further. [ABSTRACT FROM AUTHOR]

Structural and magnetic properties of Ga substituted cobalt ferrite (CoFe 2-x Ga x O 4) samples are reported in the present work. Phase purity of the prepared samples is studied with x-ray diffraction measurements. The room temperature M-H loops are measured using vibrating sample magnetometer. From the room temperature M-H data, it is observed that Ga substitution results in the soft-magnetic property in CoFe 2 O 4. Saturation magnetization is found to change for higher substitution of Ga (x > 0.2). The cation distribution with Ga substitution is estimated from the analysis of Raman spectroscopy data and in-field 57Fe Mössbauer spectroscopy measurements. Using the obtained complimentary information, it is concluded that the Fe3+ is forced to occupy more octahedral co-ordination with Ga substitution in CoFe 2 O 4. • Substitution effects of Ga in CoFe 2 O 4 (CoFe 2-x Ga x O 4) are studied. • Ga substitution in CoFe 2 O 4 results in soft-magnetic property. • Ferrimagnetic ordering is confirmed by in-field Mössbauer measurements. • Inversion parameter is observed to decrease with Ga substitution. • Fe3+ is forced to occupy more octahedral co-ordination with Ga substitution. [ABSTRACT FROM AUTHOR]