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The Tb–Co-Ga system has been investigated at 870 K by X-ray powder and microprobe elemental analyses. The existence of the known compounds TbGo 5 Ga 7 (ScFe 6 Ga 6 -type), Tb 2 Co 3 Ga 9 (Y 2 Co 3 Ga 9 -type), TbCoGa 5 (HoCoGa 5 -type), Tb 6 Co 7 Ga 21 (Ho 6 Co 7 Ga 21 -type), Tb 4 Co 3 Ga 16 (Sm 4 Co 3 Ga 16 -type), Tb 2 CoGa 8 (Ho 2 FeGa 8 -type), TbCo 3~2.8 Ga 2~2.2 (HoNi 2.6 Ga 2.4 -type), Tb 3 Co 7~5.4 Ga 2~3.6 (CeNi 3 -type), TbCo 1~1.67 Ga 1~0.33 (TiNiSi-type), Tb 2 CoGa 3 (Lu 2 CoGa 3 -type), Tb 3 Co 3 Ga (W 3 CoB 3 -type), Tb 2 Co 2 Ga (Mo 2 NiB 2 -type) and Tb 6 Co 2~2.2 Ga 1~0.8 (Ho 6 Co 2 Ga-type) has been confirmed, the TbCo 6.7-5.5 Ga 0.3-1.5 (TbCu 7 -type) is suggested, meanwhile new MgZn 2 -type TbCo 1.33 Ga 0.67 , Er 12 Ni 5 Ga 3 -type Tb 12 Co 5~5.5 Ga 3~2.5 and Sm 26 Co 11 Ga 6 -type Tb 26 Co 5~9.4 Ga 12~7.6 were detected at 870 K. Quasi-binary solid solutions were detected for Tb 2 Co 17 , TbCo 5 , Tb 2 Co 7 , TbCo 3 , TbCo 2 , TbGa 2 and Tb 5 Ga 3 at 870, while no appreciable solubility was observed for the other binary compounds in the Tb–Co-Ga system. Magnetic properties of the Tb 4 Co 3 Ga 16 , Tb 2 CoGa 3 , Tb 3 Co 7 Ga 2 , Tb 3 Co 8 Ga and Tb 26 Co 9.4 Ga 7.6 compounds have been studied this work. Tb 4 Co 3 Ga 16 is antiferromagnetic, while Tb 2 CoGa 3 , Tb 3 Co 7 Ga 2 , Tb 3 Co 8 Ga and Tb 26 Co 9.4 Ga 7.6 exhibit mixed ferro-antiferromagnetic ordering. Additionally, new Er 12 Ni 5 Ga 3 -type {Dy, Ho} 12 Co 5.5 Ga 2.5 , Sm 26 Co 11 Ga 6 -type Gd 26 Co 9.2 Ga 7.8 , Dy 26 Co 8 Ga 9 , Er 26 Co 5 Ga 12 compounds and Cr 5 Ga 3 -type Dy 5 Co 0.9 Ga 2.1 quasi-binary solid solution have been detected in this work. The Tb–Co-Ga system has been investigated at 870 K by X-ray powder and microprobe elemental analyses. The existence of the known compounds TbGo 5 Ga 7 (ScFe 6 Ga 6 -type), Tb 2 Co 3 Ga 9 (Y 2 Co 3 Ga 9 -type), TbCoGa 5 (HoCoGa 5 -type), Tb 6 Co 7 Ga 21 (Ho 6 Co 7 Ga 21 -type), Tb 4 Co 3 Ga 16 (Sm 4 Co 3 Ga 16 -type), Tb 2 CoGa 8 (Ho 2 FeGa 8 -type), TbCo 3~2.8 Ga 2~2.2 (HoNi 2.6 Ga 2.4 -type), Tb 3 Co 7~5.4 Ga 2~3.6 (CeNi 3 -type), TbCo 1~1.67 Ga 1~0.33 (TiNiSi-type), Tb 2 CoGa 3 (Lu 2 CoGa 3 -type), Tb 3 Co 3 Ga (W 3 CoB 3 -type), Tb 2 Co 2 Ga (Mo 2 NiB 2 -type) and Tb 6 Co 2~2.2 Ga 1~0.8 (Ho 6 Co 2 Ga-type) has been confirmed, the TbCo 6.7-5.5 Ga 0.3-1.5 (TbCu 7 -type) is suggested, meanwhile new MgZn 2 -type TbCo 1.33 Ga 0.67 , Er 12 Ni 5 Ga 3 -type Tb 12 Co 5~5.5 Ga 3~2.5 and Sm 26 Co 11 Ga 6 -type Tb 26 Co 5~9.4 Ga 12~7.6 were detected at 870 K. Quasi-binary solid solutions were detected for Tb 2 Co 17 , TbCo 5 , Tb 2 Co 7 , TbCo 3 , TbCo 2 , TbAl 2 and Tb 5 Ga 3 at 870, while no appreciable solubility was observed for the other binary compounds in the Tb–Co-Ga system. Magnetic properties of the Tb 4 Co 3 Ga 16 , Tb 2 CoGa 3 , Tb 3 Co 7 Ga 2 , Tb 3 Co 8 Ga and Tb 26 Co 9.4 Ga 7.6 compounds have been studied and are presented in this work. New Er 12 Ni 5 Ga 3 -type {Dy, Ho} 12 Co 5.5 Ga 2.5 , Sm 26 Co 11 Ga 6 -type Gd 26 Co 9.2 Ga 7.8 , Dy 26 Co 8 Ga 9 , Er 26 Co 5 Ga 12 compounds and Cr 5 Ga 3 -type Dy 5 Co 0.9 Ga 2.1 quasi-binary solid solution have been detected in this work. Image 1 • Tb–Co-Ga system was obtained at 870 K. • Ten known ternary terbium cobalt gallides were confirmed in Tb–Co-Ga. • Three new ternary compounds were detected in Tb–Co-Ga. • Five new ternary compounds were detected in R -Co-Ga. • Magnetic properties of five terbium cobalt gallides were investigated. [ABSTRACT FROM AUTHOR]

Abstract Magnetic ordering of the polycrystalline YNi 4 Si-type YNi 4 Si, disordered YNi 4 Si-type TbNi 4 Si and NdNi 3 CoSi (space group Cmmm , N 65, oC 12), and CaCu 5 -type NdNi 3 T Si ( T = Mn, Fe, Cu) and Sm 1-x Tb x Ni 3 FeSi (x = 0.25 and 0.5) solid solutions (space group P6/mmm , N 191, hP 6) have been studied by magnetization measurements. Down to 2 K, YNi 4 Si is paramagnetic, whereas TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi and NdNi 3 CuSi show ferromagnetic ordering (T C ) at 30 K, 71 K, 120 K, 20 K and 5.6 K and field sensitive transitions (T m ) at 10 K, 43 K, 63 K, 16 K and 3.8 K, respectively. Sm.75 Tb.25 Ni 3 FeSi and Sm.5 Tb.5 Ni 3 FeSi show ferromagnetic-antiferromagnetic transformations below ferromagnetic ordering at 166 K and 120 K, respectively. Magnetocaloric effect (MCE) of TbNi 4 Si, NdNi 3 {Mn, Co, Cu}Si, Sm.75 Tb.25 Ni 3 FeSi and Sm.5 Tb.5 Ni 3 FeSi compounds were estimated in terms of isothermal magnetic entropy change (ΔS m ). Among these compounds, TbNi 4 Si and NdNi 3 CuSi show maximal MCE with ΔS m of − 9.95 J/kg K (RCP 50 kOe ~ 180 J/kg) at 26–30 K and − 6.29 J/kg K (RCP 50 kOe ~ 31 J/K) at 6 K in a field change of 50 kOe, respectively. Below T m , TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi, NdNi 3 CuSi and Sm.5 Tb.5 Ni 3 FeSi show hard magnetic properties with coercivity of 2.2 kOe, 4.8 kOe, 4.8 kOe, 9.5 kOe, 1 kOe and 15 kOe at 2 K, respectively. Sm.75 Tb.25 Ni 3 FeSi shows a coercivity of 39 kOe at 40 K. Graphical abstract The magnetic ordering of the polycrystalline YNi 4 Si-type YNi 4 Si, disordered YNi 4 Si-type TbNi 4 Si and NdNi 3 CoSi (space group Cmmm , N 65, oC 12), and CaCu 5 -type NdNi 3 T Si ( T = Mn, Fe, Cu) and Sm 1-x Tb x Ni 3 FeSi (x = 0.25 and 0.5) solid solutions (space group P6/mmm , N 191, hP 6) have been studied by magnetization measurements. Down to 2 K, YNi 4 Si is paramagnetic, whereas TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi and NdNi 3 CuSi show ferromagnetic ordering (T C ) at 30 K, 71 K, 120 K, 20 K and 5.6 K and field sensitive transitions (T m ) at 10 K, 43 K, 63 K, 16 K and 3.8 K, respectively. Sm.75 Tb.25 Ni 3 FeSi and Sm.5 Tb.5 Ni 3 FeSi show ferromagnetic-antiferromagnetic transformations below ferromagnetic ordering at 166 K and 120 K, respectively. Among these solid solutions, TbNi 4 Si and NdNi 3 CuSi show maximal MCE with ΔS m of −9.95 J/kg K (RCP 50 kOe ~ 180 J/kg) at 26–30 K and −6.29 J/kg K (RCP 50 kOe = 31 J/K) at 6 K for NdNi 3 CuSi for a field change of 50 kOe, respectively. Below T m , TbNi 4 Si, NdNi 3 MnSi, NdNi 3 FeSi, NdNi 3 CoSi, NdNi 3 CuSi and Sm.5 Tb.5 Ni 3 FeSi are permanent magnets with coercivity of 2.2 kOe, 4.8 kOe, 4.8 kOe, 9.5 kOe, 1 kOe and 15 kOe at 2 K, respectively. Sm.75 Tb.25 Ni 3 FeSi shows a coercivity of 39 kOe at 40 K. fx1 Highlights • Disordered YNi 4 Si-type as-cast TbNi 4 Si and NdNi 3 CoSi show complex F-AF ordering. • CaCu 5 -type NdNi 3 {Mn, Fe, Cu}Si and Sm 1-x Tb x Ni 3 FeSi show complex F-AF ordering. • As-cast TbNi 4 Si and NdNi 3 CuSi show maximal MCE from these compounds. • NdNi 3 CoSi shows a coercivity of 9.5 kOe with M res /fu = 1.77 μ B at 2 K. • Sm.75 Tb.25 Ni 3 FeSi exhibits a coercivity of 39 kOe with M res /fu = 0.49 μ B at 40 K. [ABSTRACT FROM AUTHOR]

The Gd-Co-Al system has been investigated at 870/1070 K by X-ray and elemental EDS analyses. The existence of the known compounds Gd 2 Co 3 Al 9 (Y 2 Co 3 Ga 9 -type), Gd 3 Co 4.5 Al 11.5 (Gd 3 Co 4.6 Al 11 ) (Gd 3 Ru 4 Al 12 -type), Gd 3 Co 6–7.4 Al 3–1.6 (CeNi 3 -type), GdCo 1.15–0.65 Al 0.85–1.35 (MgZn 2 -type), Gd 2 Co 2 Al (Mo 2 NiB 2 -type) and Gd 3 Co 3.5–3.25 Al 0.5–0.75 (W 3 CoB 3 -type) has been confirmed at 870/1070 K. Structure types have been determined for Gd 2 Co 6 Al 19 (U 2 Co 6 Al 19 -type), Gd 7 Co 6 Al 7 (Pr 7 Co 6 Al 7 -type), Gd 6 Co 2–2.21 Al 1–0.79 (Ho 6 Co 2 Ga-type) and Gd 14 Co 3.2 Al 2.8 (Gd 14 Co 2.58 Al 3.42 at 970 K) (Lu 14 Co 3 In 3 -type). The structures of Gd 6 Co 2 Al, Gd 6 Co 2.21 Al 0.79 and Gd 14 Co 2.58 Al 3.42 flux-grown at 970 K have been refined from the single crystal X-ray diffraction data. Additionally, new ternary compounds Gd 2 Co 5.7–5.3 Al 1.3–1.7 (Er 2 Co 7 -type) and ~Gd 58 Co 20 Al 22 (unknown type structure) have been identified. Quasi-binary solid solutions were detected for Gd 2 Co 17 , GdCo 5 , Gd 2 Co 7 , GdCo 3 , GdCo 2 and GdAl 2 at 870/1070 K, while no appreciable solubility was observed for the other binary compounds in the Gd-Co-Al system. Magnetic properties of the Gd 2 Co 3 Al 9 , Gd 3 Co 4.6 Al 11 , Gd 7 Co 6 Al 7 , Gd 6 Co 2.2 Al 0.8 and Gd 14 Co 2.58 Al 3.42 compounds have been studied and are presented in this work. Gd 6 Co 2.2 Al 0.8 , Gd 3 Co 4.6 Al 11 , Gd 7 Co 6 Al 7 and Gd 14 Co 2.58 Al 3.42 order ferromagnetically, while Gd 2 Co 3 Al 9 displays antiferromagnetic transition. Additionally, {Y, Sm, Tb - Tm} 2 Co 6 Al 19 (U 2 Co 6 Al 19 -type), Yb 2 Co 3 Al 9 (Y 2 Co 3 Ga 9 -type), {Y, Sm, Tm, Yb} 3 Co 4.6 Al 11 (Gd 3 Ru 4 Al 12 -type) and Tb 7 Co 6 Al 7 (Pr 7 Co 6 Al 7 -type) compounds have been synthesized and investigated. [ABSTRACT FROM AUTHOR]

The magnetic ordering of Mo 2 NiB 2 -type Sm 2 Co 2 Al and Sm 2 Co 2 Ga ( Immm , No. 71, oI 10) compounds has been established using bulk magnetic measurements. Polycrystalline Sm 2 Co 2 Al and Sm 2 Co 2 Ga undergo ferromagnetic transitions (T C ) at 50 K and 62 K, respectively, and low-temperature field induced transitions (T m ) around 14 K and 16 K (in a field of 10 kOe), respectively. Between T C and T m Sm 2 Co 2 Al and Sm 2 Co 2 Ga are soft ferromagnets. Below T m Sm 2 Co 2 Al and Sm 2 Co 2 Ga exhibit permanent magnet properties with a residual magnetization per samarium of 0.38 μ B and 0.36 μ B , respectively, and a large coercive field of 69 kOe and 72 kOe, respectively, at 5 K. The magnetocaloric effects of Sm 2 Co 2 Al and Sm 2 Co 2 Ga were calculated in terms of isothermal magnetic entropy change and they reach maximum values of −1.62 J/kg K and −1.31 J/kg K for a field change of 50 kOe at 50 K and 58 K, respectively. Low temperature magnetic ordering with enhanced anisotropy in Sm 2 Co 2 Al and Sm 2 Co 2 Ga is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +1.63 J/kg K and +1.06 J/kg K for a field change of 50 kOe at 10 K and 8 K, respectively. [ABSTRACT FROM AUTHOR]

The crystal structure of new W 3 CoB 3 -type {Y, Gd - Ho} 3 Co 3.25 Al 0.75 , Gd 3 Co 3.5 Al 0.5 and Tb 3 Co 3 Al compounds ( Cmcm . N 63, oC 28) has been established using powder X-ray diffraction studies. The magnetic properties of Gd 3 Co 3.5 Al 0.5 , Gd 3 Co 3.25 Al 0.75 and Tb 3 Co 3.25 Al 0.75 were determined by bulk magnetization measurements and neutron diffraction studies. Gd 3 Co 0.5 Al 0.5 , Gd 3 Co 3.25 Al 0.75 and Tb 3 Co 3.25 Al 0.75 exhibit ferrimagnetic ordering below 196 K, 161 K and 151 K, respectively. Tb 3 Co 3.25 Al 0.75 shows a spin-reorientation transition at ~42 K. Below the ferrimagnetic ordering temperature Gd 3 Co 3.25 Al 0.75 and Tb 3 Co 3.25 Al 0.75 are soft ferrimagnets, meanwhile Tb 3 Co 3.25 Al 0.75 shows magnetic hardness below the spin-reorientation transition with remanent magnetization per formula unit of 9.7 μ B and coercive field of 15 kOe at 2 K. The magnetocaloric effects of Gd 3 Co 3.25 Al 0.75 and Tb 3 Co 3.25 Al 0.75 were calculated in terms of isothermal magnetic entropy change and they reach maximum values of −4.9 J/kg·K at 135–145 K and −3.7 J/kg·K at 115–135 K, respectively, for a field change of 0–50 kOe. Low temperature magnetic ordering in Tb 3 Co 3.25 Al 0.75 is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +13.6 J/kg·K at 10 K for a field change of 0–50 kOe and +0.9 J/kg K at 45 K for a field change of 0–10 kOe. Neutron diffraction study in zero applied field shows mixed ferro-antiferromagnetic ordering of Tb 3 Co 3.25 Al 0.75 with a wave vector K 0 =[0, 0, 0]. Below ~ 137 K Tb 3 Co 3.25 Al 0.75 exhibits non-collinear ferrimagnetic ordering of terbium and cobalt sublattices with resulting of b -axis ferromagnetic and c -axis antiferromagnetic components of Cmc′m ={ 1 , m x }×{ 1 , m z /[0, 0, 1/2]}×{ 1 , i′ }×{ 1 , 1 /[1/2, 1/2, 0]} magnetic space group. The spin-reorientation transition in Tb 3 Co 3.25 Al 0.75 below ~38 K corresponds to appearance of additional a -axis ferromagnetic component and decreasing of symmetry of magnetic ordering down to C2′/c ={ 1 , m z /[0, 0, 1/2]}×{ 1 , i′ }×{ 1 , 1 /[1/2, 1/2, 0]} magnetic space group. [ABSTRACT FROM AUTHOR]

The crystal structure of novel Sm 26 Co 11 Ga 6 -type {Gd - Er} 26 Ni 6.5-8 Ga 10.5-9 compounds (space group P 4/ mbm , N 127, tP 86) has been established using powder X-ray diffraction. The magnetic ordering and magnetocaloric effect of polycrystalline Er 26 Co 9 Ga 8 , Tb 26 Ni 8 Ga 9 and Tb 26 Co 9.4 Ga 7.6 have been investigated using magnetic and heat capacity measurements. Er 26 Co 9 Ga 8 and Tb 26 Ni 8 Ga 9 show mixed ferro-antiferromagnetic ordering and remarkable permanent magnet properties at low temperatures. Er 26 Co 9 Ga 8 exhibits a large magnetocaloric effect with magnetic entropy change of −11.8 ​J/kg⋅K at 12 ​K and adiabatic temperature of 9.6 ​K for a field change of 50 ​kOe. The 'Gd 26 Ni 8 Ga 9 ' alloy is composed of 88 ​wt% of Gd 26 Ni 8 Ga 9 and 12 ​wt% of GdNi which are both soft ferromagnetic. Due to their close Curie temperatures, the composite of Gd 26 Ni 8 Ga 9 and GdNi displays a table-like magnetocaloric effect with a wide temperature range from 68 ​K to 103 ​K. The crystal structure of novel Sm 26 Co 11 Ga 6 -type {Gd - Er} 26 Ni 6.5-8 Ga 10.5-9 compounds (space group P 4/ mbm , N 127, tP 86) has been established using powder X-ray diffraction. The magnetic ordering and magnetocaloric effect of polycrystalline Er 26 Co 9 Ga 8 , Tb 26 Ni 8 Ga 9 and Tb 26 Co 9.4 Ga 7.6 have been investigated using magnetic and heat capacity measurements. Er 26 Co 9 Ga 8 and Tb 26 Ni 8 Ga 9 show mixed ferro-antiferromagnetic ordering and remarkable permanent magnet properties at low temperatures. Er 26 Co 9 Ga 8 exhibits a large magnetocaloric effect with magnetic entropy change of −11.8 ​J/kg⋅K at 12 ​K and adiabatic temperature of 9.6 ​K for a field change of 50 ​kOe. The 'Gd 26 Ni 8 Ga 9 ' alloy is composed of 88 ​wt% of Gd 26 Ni 8 Ga 9 and 12 ​wt% of GdNi which are both soft ferromagnetic. Due to their close Curie temperatures, the composite of Gd 26 Ni 8 Ga 9 and GdNi displays a table-like magnetocaloric effect with a wide temperature range from 68 ​K to 103 ​K. [Display omitted] • Er 26 Co 9 Ga 8 and Tb 26 Ni 8 Ga 9 show mixed F-AF ordering below 12 ​K and 82 ​K. • They exhibit permanent magnet properties at low temperatures. • MCE of Tb 26 Co 9.4 Ga 7.6 , Er 26 Co 9 Ga 8 , Gd 26 Ni 8 Ga 9 and Tb 26 Ni 8 Ga 9 are investigated. • Er 26 Co 9 Ga 8 shows largest adiabatic temperature due to low heat capacity. • Two-phase 'Gd 26 Ni 8 Ga 9 ' show a table-like MCE from 68 ​K to 103 ​K. [ABSTRACT FROM AUTHOR]

Abstract: Nanocrystalline (14–18nm) anatase TiO2 powders with high photocatalytic activity are synthesized by a sol–gel method followed by supercritical drying in isopropanol. The photocatalytic behavior is studied in the model reaction of phenol photodegradation in water. The relationship between photoactivity, crystal structure, texture, charge-carrier lifetimes, bandgap energies and thermal treatment of products is discussed. The effective method of synthesis of photocatalysts based on TiO2—sol–gel method followed by supercritical drying in isopropanol is presented. It shows, that the obtained powders can be used in photocatalytical depollution without additional thermal treatment. [Copyright &y& Elsevier]

The oxidation kinetics of Bi[sub 1.3]Pb[sub 0.8]Sr[sub 2]Ca[sub 0.8]Y[sub 0.2]Cu[sub 2]O[sub 8 + δ] solid solutions at different temperatures and p[sub O[sub 2]] = 0.21 atm is investigated by thermogravimetry. The results obtained are compared with the previously studied oxidation kinetics of Bi[sub 1.5]Pb[sub 0.6]Sr[sub 2]CaCu[sub 2]O[sub 8 + δ] solid solutions. It is found that the substitution of yttrium for calcium leads to an appreciable retardation of the initial oxidation stage associated with the oxygen diffusion. The phonon spectra of the solid solutions are examined using inelastic neutron scattering on a DIN-2PI direct-geometry spectrometer. The high-frequency (>50 meV) phonon densities of states for yttrium-containing and yttrium-free solid solutions are analyzed. The possible model is proposed for a correlation between the differences observed in the high-frequency phonon densities of states attributed to the vibrations of oxygen atoms and the differences in the oxidation kinetics of the solid solutions under consideration. © 2004 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

The Ce–Ni-Ga system has been investigated at 670/870 ​K by X-ray and electron microprobe analyses. The known compounds, i.e. CeNi 9 Ga 4 and CeNi 5.7 Ga 7.3 (LaCo 9 Si 4 -type), CeNi 7 Ga 6 (LaNi 7 In 6 -type), CeNi 6.5-6.15 Ga 6.5-6.85 (Ce 2 Ni 13 Ga 13 -type), CeNi 3-3.2 Ga 2-1.8 (YCo 3 Ga 2 -type), CeNi 1-1.2 Ga 3-2.8 (CePtGa 3 -type), CeNiGa (ZrNiAl-type), CeNiGa 2 (NdNiGa 2 -type), Ce 2 Ni 2-2.06 Ga 1-0.94 (Mo 2 NiB 2 -type) and Ce 3 Ni 2 Ga 2 (La 3 Ni 2 Ga 2 -type), have been confirmed in this system at 870 ​K. A new ter nary Ce 2 Ni 6 Ga (Er 2 Co 7 -type, R-3m, N 166–2, hP54) was detected at 870 ​K and ~Ce 5 Ni 2 Ga (unknown type structure) was identified at 670 ​K in this system. Quasibinary solid solutions were detected at 870 ​K for CeNi 5 , CeNi 3 and CeGa 2 while no appreciable solubility was observed for other binary compounds of the Ce–Ni-Ga system. CeNi 6.5 Ga 6.5 , CeNi 7 Ga 6 and CeNi 9 Ga 4 are Curie-Weiss paramagnets down to 2 ​K, exhibiting magnetic-field-induced ferromagnetism and field-enhanced heat capacity at low temperatures. CeNiGa 2 , CeNiGa 3 and Ce 5 Ni 2 Ga are antiferromagntics with the Néel temperatures at 4–6 ​K and Curie-Weiss paramagnetics at high temperatures. CeNi 3 Ga 2 , CeNiGa and Ce 2 Ni 2 Ga show temperature insensitive paramagnetism at high temperatures and Curie-Weiss paramagnetism at low temperature, suggesting a mixed valence state of Ce(III) and Ce(IV). Image 1 [ABSTRACT FROM AUTHOR]

The Tb-Fe-Ga system has been investigated at 870 ​K by X-ray powder, microprobe elemental analyses and magnetic measurements. The existence of the known compounds TbFe 6.2-5.5 Ga 5.8-6.5 (ScFe 6 Ga 6 -type), TbFe 5.5-4.9 Ga 6.5-7.1 (ThMn 12 -type), TbFe 2.4-2.2 Ga 0.6-0.8 (CeNi 3 -type), Tb 4 FeGa 12 (Y 4 PdGa 12 -type) and quasibinary solid solutions Th 2 Zn 17 -type Tb 2 Fe 17-10.6 Ga 0-6.4 , PuNi 3 -type TbFe 3-2.73 Ga 0-0.23 and MgCu 2 -type TbFe 2-1.57 Ga 0-0.43 has been confirmed, meanwhile new Th 2 Ni 17 -type Tb 1.85 Fe 15.2 Ga 1.8 and AlB 2 -type TbFe 0-0.3 Ga 2-1.7 were detected at 870 ​K. The appreciable solubility was no observed at the other binary compounds in the Tb-Fe-Ga system. Tb 4 FeGa 12 is pure antiferromagnetic and TbFe 0.3 Ga 1.7 shows mixed field-sensitive ferro-antiferromagnetic ordering. TbFe 6.2 Ga 5.8 , TbFe 5.5 Ga 6.5 , TbFe 2.4 Ga 0.6 , and TbFe 1.42 Ga 0.58 exhibit ferrimagnetic ordering of Tb- and Fe-sublattices, which are soft ferromagnets at room temperature and hard magnets at low temperatures. The Tb-Fe-Ga system has been investigated at 870 ​K by X-ray powder, microprobe elemental analyses and magnetic measurements. The known compounds TbFe 6.2-5.5 Ga 5.8-6.5 (ScFe 6 Ga 6 -type), TbFe 5.5-4.9 Ga 6.5-7.1 (ThMn 12 -type), TbFe 2.4-2.2 Ga 0.6-0.8 (CeNi 3 -type), Tb 4 FeGa 12 (Y 4 PdGa 12 -type) and quasibinary solid solutions Th 2 Zn 17 -type Tb 2 Fe 17-10.6 Ga 0-6.4 , PuNi 3 -type TbFe 3-2.73 Ga 0-0.23 and MgCu 2 -type TbFe 2-1.57 Ga 0-0.43 has been confirmed, meanwhile new Th 2 Ni 17 -type Tb 1.85 Fe 15.2 Ga 1.8 and AlB 2 -type TbFe 0-0.3 Ga 2-1.7 were detected at 870 ​K Tb 4 FeGa 12 is pure antiferromagnetic and TbFe 0.3 Ga 1.7 shows mixed field-sensitive ferro-antiferromagnetic ordering. TbFe 6.2 Ga 5.8 , TbFe 5.5 Ga 6.5 , TbFe 2.4 Ga 0.6 , and TbFe 1.42 Ga 0.58 exhibit ferrimagnetic ordering of Tb- and Fe-sublattices, which are soft ferromagnets at room temperature and hard magnets at low temperatures. Image 1 • Tb-Fe-Ga system was obtained at 870 ​K. • Four known ternary terbium iron gallides were confirmed in Tb-Fe-Ga at 870 ​K. • AlB 2 -type TbGa 2 and Th 2 Ni 17 -type Tb 2 Fe 17 qusibinary solid solutions were detected at 870 ​K. • Tb 4 FeGa 12 is pure AF, TbFe 0.3 Ga 1.7 shows mixed field-sensitive F-AF ordering. • TbFe 6.2 Ga 5.8 , TbFe 5.5 Ga 6.5 , TbFe 2.4 Ga 0.6 , TbFe 1.42 Ga 0.58 are soft ferromagnets at room temperature. • They are hard magnets at low temperatures. [ABSTRACT FROM AUTHOR]

The magnetic ordering of polycrystalline Ho 6 Co 2 Ga-type Gd 6 Co 2.2 Al 0.8 , Tb 6 Co 2.2 Al 0.8 , Tb 6 Co 2 Al and Dy 6 Co 2.2 Al 0.8 (space group Immm , N 71, oI 36) has been established using magnetic measurements and the magnetic structure of Tb 6 Co 2.2 Al 0.8 has been resolved by the neutron diffraction study. Gd 6 Co 2.2 Al 0.8 exhibits field sensitive ferro-antiferromagnetic ordering, meanwhile Tb 6 Co 2.2 Al 0.8 , Tb 6 Co 2 Al and Dy 6 Co 2.2 Al 0.8 are antiferromagnets with metamagnetic transformation of magnetic ordering. Gd 6 Co 2.2 Al 0.8 is soft ferromagnet, whereas Tb 6 Co 2.2 Al 0.8 , Tb 6 Co 2 Al and Dy 6 Co 2.2 Al 0.8 exhibit low-temperature weak permanent magnet properties. From these compounds, Gd 6 Co 2.2 Al 0.8 demonstrates largest magnetocaloric effect with magnetic entropy change of −10.89 J/kg⋅K at 75 K for a field change of 50 kOe (relative cooling power of ~760 J/kg). Neutron diffraction study indicates non-collinear abc -antiferromagnetic ordering of Tb 6 Co 2.2 Al 0.8 in zero applied magnetic field. Below 63 K and down to 52 K, Tb 6 Co 2.2 Al 0.8 exhibits antiferromagnetic ordering with magnetic space group I′22′2′ (wave vector K 0 = [0, 0, 0]). Below 52 K and down to 1.5 K, the magnetic structure of Tb 6 Co 2.2 Al 0.8 is sum of magnetic component with P2 1 ′2 1 2′ magnetic space group (wave vector K 0 = [0, 0, 0]) and square-modulated antiferromagnetic component along c -axis of unit cell with K 1 = [±1/4, 0, ±1/4] wave vector. Image 1 • Gd 6 Co 2.2 Al 0.8 shows F-AF ordering and it is soft ferromagnet down to 2 K. • Δ S m of Gd 6 Co 2.2 Al 0.8 reaches of −10.89 J/kg⋅K at 75 K in field change of 50 kOe. • Tb 6 Co 2.2 Al 0.8 , Tb 6 Co 2 Al and Dy 6 Co 2.2 Al 0.8 show field sensitive AF ordering. • Tb 6 Co 2.2 Al 0.8 , Tb 6 Co 2 Al and Dy 6 Co 2.2 Al 0.8 are LT weak permanent magnets. • Tb 6 Co 2.2 Al 0.8 exhibits abc -Antiferromagnetic ordering in zero applied field. [ABSTRACT FROM AUTHOR]

The magnetic ordering of Mo 2 NiB 2 -type {Gd, Tb, Dy} 2 Co 2 Al ( Immm , No. 71, oI 10) compounds has been established using bulk magnetic measurements and neutron diffraction study. Polycrystalline Gd 2 Co 2 Al, Tb 2 Co 2 Al and Dy 2 Co 2 Al undergo ferrimagnetic transitions (T C ) at 78 K, 98 K and 58 K, respectively, and low-temperature field induced transition (T m ) around 15 K, 20 K and 15 K, respectively. Between T m and T C Gd 2 Co 2 Al, Tb 2 Co 2 Al and Dy 2 Co 2 Al are soft ferrimagnets. Below T m Gd 2 Co 2 Al is soft ferrimagnet, whereas Tb 2 Co 2 Al and Dy 2 Co 2 Al exhibit permanent magnet properties with residual magnetization per rare earth of 4.95 B and 4.8 B , respectively, and large coercive field of 72 kOe and 22 kOe, respectively, at 2 K. The magnetocaloric effects of Gd 2 Co 2 Al, Tb 2 Co 2 Al and Dy 2 Co 2 Al were calculated in terms of isothermal magnetic entropy change and they reach maximum values of −10.4 J/kg K, −7.6 J/kg K and −6.6 J/kg K for a field change of 50 kOe near 75 K, 98 K and 58 K, respectively. Low-temperature transition of Gd 2 Co 2 Al is followed by the magnetic entropy change of −2.9 J/kg K in a field change of 50 kOe at 15 K. Low temperature magnetic ordering with enhanced anisotropic effects in Tb 2 Co 2 Al and Dy 2 Co 2 Al is accompanied by a positive magnetocaloric effect with isothermal magnetic entropy changes of +19.9 J/kg K at 20 K (field change 0–50 kOe) and +2.7 J/kg K at 15 K (field change 0–10 kOe), respectively. Neutron diffraction study shows that, in zero applied field, Tb 2 Co 2 Al exhibits c -axis ferrimagnetic ordering with magnetic space group Immm ′ and propagation vector K 0 = [0, 0, 0] below T C ND ∼ 111 K with M Tb = 8.86(15) B and M Co = 0.26(2) B at 2 K. [ABSTRACT FROM AUTHOR]

The crystal structure of new hexagonal MgZn 2 -type {Ho, Tm}FeGa compounds (space group P 63 /mmc , N 194, hP 12) has been established using powder X-ray diffraction studies. The magnetic properties of polycrystalline MgZn 2 -type ErFeGa compound have been studied using bulk magnetization data. ErFeGa exhibits ferromagnetic ordering at T C = 77 K and field sensitive antiferromagnetic-like ordering at T m ~ 58 K in field of 100 Oe and T m ~ 10 K in field of 5 kOe. The paramagnetic susceptibility follows Curie-Weiss law with effective paramagnetic moment per formula unit (M eff /fu) of 9.59 μ B and paramagnetic Weiss temperature (Θ P ) of 27 K. At 2 K, ErFeGa exhibits hard magnetic properties with remanent magnetization per formula unit (M res /fu) of 3.7 μ B , coercive field (H coer ) of 8.2 kOe and critical field (H crit ) of ~9.6 kOe. The magnetocaloric effect of ErFeGa has been calculated in terms of isothermal magnetic entropy change (ΔS m ) and maximum ΔS m values are −5.5 J/kg K for a field change of 0–50 kOe (relative cooling power RCP 50 kOe ~ 410 J/kg), −13.0 J/kg K for a field change of 0–140 kOe (RCP 140 kOe ~ 1230 J/kg) at 70 K and +1.7 J/kg K for a field change of 0–10 kOe at 10 K (RCP 10 kOe ~ 34 J/kg). [ABSTRACT FROM AUTHOR]

The Tb-Mn-Ga system has been investigated at 870/1070 ​K by X-ray powder diffraction and microprobe elemental analyses. The existence of the known compounds Tb 2 Mn 11.7-15 Ga 5.3-2 (Th 2 Ni 17 -type), Tb 2 Mn 10.2 Ga 6.8 (Th 2 Zn 17 -type), TbMn 5.4-4.5 Ga 6.6-7.5 (ThMn 12 -type), Tb 2 Mn 0.3-0.7 Ga 6 (K 2 PtCl 6 -type), TbMnGa (ZrNiAl-type), Tb 2 MnGa 3 (CeCu 2 -type), TbMn 0.26 Ga 1.74 (CaIn 2 -type) and quasibinary solid solutions ThMn 12 -type TbMn 12-10.9 Ga 0-1.1 , MgCu 2 -type TbMn 2-1.4 Ga 0-0.6 and AlB 2 -type TbMn 0-0.2 Ga 2-1.8 has been confirmed in the Tb-Mn-Ga system at 870/1070 ​K. The appreciable solubility of other binaries was no observed in the Tb-Mn-Ga system. The K 2 PtCl 6 -type Tb 2 Mn 0.5 Ga 6 compound shows mixed ferro-antiferromagnetic ordering with high-temperature ferromagnetic ordering (T C) of 28 ​K and antiferromagnetic transformation of magnetic ordering (T N) at 20 ​K. The Tb-Mn-Ga system has been investigated at 870/1070 ​K by X-ray powder, microprobe elemental analyses and magnetic measurements. The known compounds Tb 2 Mn 11.7-15 Ga 5.3-2 (Th 2 Ni 17 -type), Tb 2 Mn 10.2 Ga 6.8 (Th 2 Zn 17 -type), TbMn 5.4-4.5 Ga 6.6-7.5 (ThMn 12 -type), Tb 2 Mn 0.3-0.7 Ga 6 (K 2 PtCl 6 -type), TbMnGa (ZrNiAl-type), Tb 2 MnGa 3 (CeCu 2 -type), TbMn 0.26 Ga 1.74 (CaIn 2 -type) and quasibinary solid solutions ThMn 12 -type TbMn 12-10.9 Ga 0-1.1 , MgCu 2 -type TbMn 2-1.4 Ga 0-0.6 and AlB 2 -type has been confirmed in the Tb-Mn-Ga system at 870/1070 ​K. The appreciable solubility was no observed at the other binary compounds in the Tb-Mn-Ga system. K 2 PtCl 6 -type Tb 2 Mn 0.5 Ga 6 shows mixed ferro-antiferromagnetic ordering with high-temperatur ferromagnetic ordering (T C) of 28 ​K and antiferromagnetic transformation of magnetic ordering (T N) at 20 ​K. [Display omitted] • Tb-Mn-Ga system was obtained at 870/1070 ​K. • The known ternary terbium manganese gallides were confirmed in Tb-Mn-Ga at 870/1070 ​K. • K 2 PtCl 6 -type Tb 2 Mn 0.3-0.7 Ga 6 shows homogeneity area at 870 ​K. • Tb 2 Mn 0.5 Ga 6 exhibits field-sensitive ferro-antiferromagnetic ordering. • This is confirmed via magnetic entropy change and magnetic hysteresis up to 90 ​kOe. [ABSTRACT FROM AUTHOR]

The Ce-Ni-Si system has been investigated at 870/1070 K by X-ray and microprobe analyses. The existence of the known compounds, i.e. : Ce 2 Ni 15.8 Si 1.2 (Th 2 Ni 17 -type), Ce 2 Ni 15-14 Si 2-3 (Th 2 Zn 17 -type), CeNi 8.6 Si 2.4 (BaCd 11 -type), CeNi 8.8 Si 4.2 (LaCo 9 Si 4 -type), CeNi 6 Si 6 (CeNi 6 Si 6 -type), CeNi 5 Si 1-0.3 (TbCu 7 -type), CeNi 4 Si (YNi 4 Si-type), CeNi 2 Si 2 (CeGa 2 Al 2 -type), Ce 2 Ni 3 Si 5 (U 2 Co 3 Si 5 -type), Ce 3 Ni 6 Si 2 (Ce 3 Ni 6 Si 2 -type), Ce 3 Ni 4 Si 4 (U 3 Ni 4 Si 4 -type), CeNiSi 2 (CeNiSi 2 -type), ~CeNi 1.3 Si 0.7 (unknown type structure), Ce 6 Ni 7 Si 4 (Pr 6 Ni 7 Si 4 -type), CeNiSi (LaPtSi-type), CeNi 0.8-0.3 Si 1.2-1.7 (AlB 2 -type), ~Ce 2 Ni 2 Si (unknown type structure), ~Ce 4.5 Ni 3.5 Si 2 (unknown type structure), Ce 15 Ni 7 Si 10 (Pr 15 Ni 7 Si 10 -type), Ce 5 Ni 1.85 Si 3 (Ce 5 Ni 1.85 Si 3 -type), Ce 6 Ni 1.4 Si 3.4 (Ce 6 Ni 1.67 Si 3 -type), Ce 7 Ni 2 Si 5 (Ce 7 Ni 2 Si 5 -type) and Ce 3 NiSi 3 (Y 3 NiSi 3 -type) has been confirmed in this section. Moreover, the type structure has been determined for ~Ce 2 Ni 2 Si (Mo 2 NiB 2 -type Ce 2 Ni 2.5 Si 0.5 ) and ~Ce 4.5 Ni 3.5 Si 2 (W 3 CoB 3 -type Ce 3 Ni 3-2.7 Si 1-1.3 ) and new ternary phases Ce 2 Ni 6.25 Si 0.75 (Gd 2 Co 7 -type), CeNi 7-7.6 Si 6-5.4 (GdNi 7 Si 6 -type) and ~Ce 27 Ni 42 Si 31 (unknown type structure) have been identified in this system. Quasi-binary phases, solid solutions, were detected at 870/1070 K for CeNi 5 , CeNi 3 and CeSi 2 ; while no appreciable solubility was observed for the other binary compounds of the Ce-Ni-Si system. As a prolongation of Rare Earth-Ni-Si system’s isostructural rows, LaNi 7 Si 6 and YNi 6.6 Si 6.1 (GdNi 7 Si 6 -type), ScNi 6 Si 6 (YCo 6 Ge 6 -type), NdNi 6 Si 6 (YNi 6 Si 6 -type), {Tb, Ho} 2 Ni 15 Si 2 (Th 2 Zn 17 -type), Nd 2 Ni 2.3 Si 0.7 and Sm 2 Ni 2.2 Si 0.8 (Mo 2 NiB 2 -type), Nd 3 Ni 2.55 Si 1.45 (W 3 CoB 3 -type) and {Tb, Dy} 7 Ni 50 Si 19 (Y 7 Ni 49 Si 20 -type) compounds were synthesized and investigated. Magnetic properties of the CeNi 6 Si 6 , CeNi 7 Si 6 , CeNi 8.8 Si 4.2 , Ce 6 Ni 7 Si 4 , CeNi 5 Si, Ce 2 Ni 2.5 Si 0.5 , Nd 2 Ni 2.3 Si 0.7 and Dy 7 Ni 50 Si 19 compounds have also been investigated and are presented here. [ABSTRACT FROM AUTHOR]

Magnetic ordering and magnetocaloric effect of polycrystalline Ce 3 Ni 6 Si 2 -type Gd 3 Ni 6 Ga 2 (space group Im -3 m , N 229, cI 44) has been investigated via heat capacity and magnetic measurements. Gd 3 Ni 6 Ga 2 exhibits ferromagnetic ordering at T C ​= ​104 ​K and a field-sensitive transformation of magnetic ordering at T m ​= ​38 ​K. At 2 ​K, it is soft ferromagnetic with magnetic moment per Gd of 6.73 μ B in 90 ​kOe. Heat capacity measurements in zero magnetic field indicated the Debye temperature around 320 ​K and peak in heat capacity around T C , only. Gd 3 Ni 6 Ga 2 shows table-like magnetic entropy change of −4.9 ​J/kg⋅K at T C and −3.8 ​J/kg⋅K at T m in a field change of 50 ​kOe with a wide working temperature range. Magnetic ordering of polycrystalline Ce 3 Ni 6 Si 2 -type Gd 3 Ni 6 Ga 2 (space group Im -3 m , N 229, cI 44) has been investigated at 2–300 ​K via heat capacity in zero applied magnetic field and magnetic measurements in fields up to 90 ​kOe Gd 3 Ni 6 Ga 2 exhibits ferromagnetic ordering at T C ​= ​104 ​K and field-sensitive transformation of magnetic ordering at T m ​= ​38 ​K. At 2 ​K, it is soft ferromagnet with magnetic moment per Gd of 6.73 μ B in field of 90 ​kOe. Heat capacity measurements in zero magnetic field indicated Debye temperature around 320 ​K and peak in heat capacity around T C , only. Gd 3 Ni 6 Ga 2 shows magnetic entropy change of −4.9 ​J/kg⋅K at T C and −3.8 ​J/kg⋅K at T m for a field change of 50 ​kOe and its magnetic data compared with known magnetic data of isostructural Gd 3 Ni 6 Si 2 and Gd 3 Ni 6 Al 2. [Display omitted] • The magnetic ordering of Gd 3 Ni 6 Ga 2 was studied via magnetization and heat capacity. • Gd 3 Ni 6 Ga 2 shows high-temperature ferromagnetic ordering at T C ​= ​104 ​K. • It exhibits field sensitive low-temperature transformation around T m ​= ​38 ​K. • Gd 3 Ni 6 Ga 2 shows table-like magnetocaloric effect between T C and T m. [ABSTRACT FROM AUTHOR]

The polycrystalline YNiAl 4 -type GdNiGa 4 (space group Cmcm , N 63, oC 24), CeCu 2 -type GdNi 0.5 Ga 1.5 (space group Imma , N 74, oI 12) and TiNiSi-type GdNiGa (space group Pnma , N 62, oP 12) are prepared by arc melting with following annealing. The magnetic ordering and magnetocaloric effects of these compounds have been investigated using magnetic measurements in fields up to 90 ​kOe GdNiGa 4 shows field insensitive antiferromagnetic ordering below T N ​= ​12 ​K, GdNi 0.5 Ga 1.5 demonstrate ferromagnetic ordering below T C ​= ​36 ​K and low-temperature field-sensitive ferro-antiferromagnetic ordering (T m) in the range of 12–32 ​K, while GdNiGa exhibits ferromagnetic ordering below T C ​= ​28 ​K. The saturation magnetizations at 2 ​K indicate a collinear ferromagnetic ordering of Gd-sublattice in GdNi 0.5 Ga 1.5 and GdNiGa. The transformation of crystal lattice from GdNi 0.5 Ga 1.5 to GdNiGa with ordering of Ni-sublattice leads to a remarkable increasing of magnetic entropy change and magnetocaloric effect. The structural and magnetic features of ternary Gd-Ni-Ga compounds are discussed. The magnetic ordering of polycrystalline YNiAl 4 -type GdNiGa 4 (space group Cmcm , N 63, oC 24), CeCu 2 -type GdNi 0.5 Ga 1.5 (space group Imma , N 74, oI 12) and TiNiSi-type GdNiGa (space group Pnma , N 62, oP 12) has been investigated using magnetic measurements in fields up to 90 ​kOe GdNiGa 4 shows field insensitive antiferromagnetic ordering at T N ​= ​12 ​K, GdNi 0.5 Ga 1.5 shows ferromagnetic ordering below T C ​= ​36 ​K with low-temperature field-sensitive ferro-antiferromagnetic ordering (T m) in the range of 12–32 ​K, while GdNiGa exhibits ferromagnetic ordering at T C ​= ​28 ​K. The saturation magnetizations at 2 ​K indicate a collinear ferromagnetic ordering of Gd-sublattice in GdNi 0.5 Ga 1.5 and GdNiGa. The transformation of crystal lattice from GdNi 0.5 Ga 1.5 to GdNiGa with ordering of Ni-sublattice leads to a remarkable increasing of magnetic entropy change and magnetocaloric effect. The structural and magnetic features of ternary Gd-Ni-Ga compounds are discussed. [Display omitted] • The magnetic ordering and MCE of GdNiGa 4 , GdNi 0.5 Ga 1.5 and GdNiGa were determined. • GdNiGa 4 exhibits field insensitive antiferromagnetic ordering at T N ​= ​12 ​K. • Soft ferromagnet, GdNi 0.5 Ga 1.5 shows mixed ferro-antiferromagnetic ordering below T C ​= ​36 ​K. • Soft ferromagnet, GdNiGa shows ferromagnetic ordering at T C ​= ​28 ​K. • Due to ordering of Ni sublattice, GdNiGa demonstrates bigger MCE than GdNi 0.5 Ga 1.5. [ABSTRACT FROM AUTHOR]

[Display omitted] • GdNi 4 B, GdNi 4 In, GdCo 4 Al and DyCo 4.6 Si 0.4 prepared via arc-furnace melting/annealing. • GdNi 4 B and GdNi 4 In show dominant ferromagnetic ordering of Gd sublattice. • GdCo 4 Al and DyCo 4.6 Si 0.4 exhibit HT dominant ferromagnetic ordering of Co sublattice. • GdCo 4 Al and DyCo 4.6 Si 0.4 show LT with dominant ordering of rare earth sublattice. • GdNi 4 In exhibits largest magnetocaloric effect from GdNi 4 {B, Al, Ga, Si, In} compounds. The polycrystalline CeCo 4 B-type GdNi 4 B (space group P 6/ mmm , N 191, hP 12), CaCu 5 -type GdCo 4 Al and DyCo 4.6 Si 0.4 (space group P 6/ mmm , N 191, hP 6) and MgCu 4 Sn-type GdNi 4 In (space group F -43 m , N 216, cF 24) were prepared by arc melting with following annealing. The magnetic ordering and magnetocaloric effects of these compounds have been investigated using magnetic measurements in fields up to 90 kOe. GdNi 4 B and GdNi 4 In show dominant ferromagnetic ordering of Gd sublattice with T C of 39 K and 24 K, respectively with magnetic entropy change of −11.3 J/kg·K for GdNi 4 B and −11.8 J/kg·K for GdNi 4 In for a field change of 50 kOe. GdCo 4 Al and DyCo 4.6 Si 0.4 exhibit high-temperature dominant ferromagnetic ordering of Co sublattice with low-temperature spin-reorientation transformation of magnetic ordering and dominant ordering of rare earth sublattice in width temperature interval. In a field change of 50 kOe, the compensation temperature of DyCo 4.6 Si 0.4 is followed via table-like magnetic entropy change of −1.0 J/kg·K at ∼40–240 K, while GdCo 4 Al exhibits magnetic entropy change of around −0.6 J/kg·K at ∼150–300 K. [ABSTRACT FROM AUTHOR]

Ultrafine La0.7Sr0.3MnO3 powders were prepared via homogenization in chelate solutions, followed by the calcination of solid precursors at 700°C in air or oxygen, and their phase composition and average par- ficle size were determined. The solid precursors were obtained from a solution of polynuclear La, Sr, and Mn chelates (diethylenetriaminepentaacetates) by three procedures: (1) gelation of the solution, followed by air drying of the resultant gel; (2) gelation followed by microwave dehydration; and (3) microwave dehydration of the solution. The results demonstrate that the way in which the chelate solution is converted into solid foams has little effect on the phase composition and particle size of the powders. At the same time, the phase composition and particle size of the reaction products depend on the calcination atmosphere (air or oxygen). Calcination in oxygen (700°C, 10 h) ensures the preparation of phase-pure La0.7Sr0.3MnO3 powders, with an average particle size of ... 30 nm, from the three precursors. [ABSTRACT FROM AUTHOR]

An investigation of the two-component phase diagram of the CaNaPO 4 - CaKPO 4 system performed using various analysis techniques is reported. The continuous solid solution series of α-CaMPO 4 existing above 700 °C undergoes eutectoid decomposition during cooling to β-CaMPO 4 -based solid solutions enriched with Na and K, and to an intermediate nonstoichiometric compound with an ideal composition of CaK 0.6 Na 0.4 PO 4. All three compounds exhibit significant volumetric effects associated with first-order phase transitions, with positive volume changes under cooling for the intermediate compound. Increased K content in ceramics based on CaK y Na 1- y PO 4 compositions enhances the strength properties of those ceramics, including their fracture toughness, which is associated with increased density. Increased K content also has a smaller effect of inducing phase transformations accompanied by strong volume changes. [ABSTRACT FROM AUTHOR]

One of the possible ways for using silver nanoparticles (AgNPs) in spectrophotometry is their application for the determination of oxidizing agents, based on oxidative destruction of these nanoobjects. This process depends on the structure of AgNPs surface layer, which is essentially affected by the chosen stabilizer. To assess influence of the nanoparticle stabilizer and the nature of the analyte, possibilities of AgNPs covered with stabilizers of three types (citrate, polyvinylpyrrolidone, and polyhexamethylene guanidinium) for the spectrophotometric determination of hydrogen peroxide and differently substituted organic peroxides were studied. The approach is based on AgNPs oxidation leading to discoloration of the solution monitored spectrophotometrically. Different selectivity of the oxidation depending on the stabilizer was shown. Effects of various factors (time of interaction, pH, concentration of AgNPs) on the oxidation and analytical performance of the procedure were investigated. The method allows for the determination of hydrogen peroxide, peracetic acid, m -chloroperbenzoic acid, and t -butylhydroperoxide in the range of 0.3–1.5, 0.1–0.8, 1.0–7.5, and 1–7 μg mL−1 and with the limits of detection of 0.1, 0.04, 0.3, and 0.3 μg mL−1, respectively. The analysis can be performed using either spectrophotometry or naked-eye detection. Image 1 • Oxidation of AgNPs covered with stabilizers of three types by peroxides were studied. • The type of an AgNPs stabilizer plays an important role in their oxidation. • Hydrogen peroxide and differently substituted organic peroxides are considered. • Best strategies for the determination of peroxides using AgNPs are proposed. [ABSTRACT FROM AUTHOR]

Abstract Magnetic ordering of the polycrystalline Lu 14 Ni 3 In 3 -type Gd 14 Ni 3 Al 3 and Tb 14 Ni 3 Al 3 (space group P 4 2 / nmc , N 137, tP 80) has been studied by magnetization, heat capacity and neutron diffraction study. The magnetization and heat capacity measurements of Gd 14 Ni 3 Al 3 reveal the antiferromagnetic ordering at 62 K and low-temperature spin-reorientation transition at 42 K. Neutron diffraction study in zero applied magnetic field indicates non-collinear antiferromagnetic ordering of Tb 14 Ni 3 Al 3. It exhibits abc -antiferromagnetic ordering with magnetic space group P2 1 ′/c′ (wave vector K 0 = [0, 0, 0]) below 47 K and slight reorientation of terbium magnetic moments between 16 K and 36 K. Graphical abstract Image 1 Highlights • {Gd, Tb} 14 Ni 3 Al 3 demonstrate pure antiferromagnetic ordering. • Gd 14 Ni 3 Al 3 exhibits antiferromagnetic transitions at T N = 62 K and T m = 42 K. • Gd 14 Ni 3 Al 3 shows field induced weak ferromagnetism. • Tb 14 Ni 3 Al 3 exhibits abc -AF ordering with wave vector K 0 = [0, 0, 0] in zero field. • abc -AF ordering of Tb 14 Ni 3 Al 3 meets to magnetic space group P2 1 ′/c′. [ABSTRACT FROM AUTHOR]

The gas cluster ion beam technique was used for the silicon carbide crystal surface smoothing. The effect of processing by two inert cluster ions, argon and xenon, was quantitatively compared. While argon is a standard element for GCIB, results for xenon clusters were not reported yet. Scanning probe microscopy and high resolution transmission electron microscopy techniques were used for the analysis of the surface roughness and surface crystal layer quality. The gas cluster ion beam processing results in surface relief smoothing down to average roughness about 1 nm for both elements. It was shown that xenon as the working gas is more effective: sputtering rate for xenon clusters is 2.5 times higher than for argon at the same beam energy. High resolution transmission electron microscopy analysis of the surface defect layer gives values of 7 ± 2 nm and 8 ± 2 nm for treatment with argon and xenon clusters. [ABSTRACT FROM AUTHOR]

Positively charged polyhexamethylene guanidine hydrochloride-stabilized silver nanoparticles (PHMG-AgNPs) were prepared and applied as a colorimetric probe for single-step determination of pyrophosphate and sulfate. The approach is based on the nanoparticles aggregation leading to change in their absorption spectra and color of the solution. Due to both electrostatic and steric stabilization these nanoparticles show decreased sensitivity relatively to many common anions, which allows for simple and rapid direct single-step determination of pyrophosphate and sulfate. Effects of different factors (time of interaction, pH, concentrations of anions and the nanoparticles) on aggregation of PHMG-AgNPs and analytical performance of the procedure were investigated. The method allows for the determination of pyrophosphate and sulfate in the range of 0.16–2 μg mL −1 and 20–80 μg mL −1 with RSD of 2–5%, respectively. The analysis can be performed using either spectrophotometry or naked-eye detection. Practical application of the method was shown by the example of pyrophosphate determination in baking powder sample. [ABSTRACT FROM AUTHOR]

Composite electrode materials Li[Li 0.13 Ni 0.2 Mn 0.47 Co 0.2 ]O 2 (LNMC)–CeO 2 –С are obtained by the coprecipitation of Co, Ni, Mn and Ce hydroxides followed by the coating of LNMC–CeO 2 composites with pyrolytic carbon. The introduction of 5% CeO 2 promotes the reduction of LNMC grain size from 190–230 to 100–170 nm and the corresponding increase in the electrochemical capacity of LNMC-CeO 2 composite. The pyrolytic coating consists of the network of 2–5 nm polymer-carbon particles at the surface of LNMC crystallites. The electrochemical impedance spectroscopy data, which was performed after the galvanostatic cycling, demonstrated considerably lower charge transfer resistance of the carbon-coated composites compared to the bare LNMC and the LNMC-CeO 2 composites. The values of the discharge capacity of LNMC-CeO 2 -C composites are superior to the capacity of LMNC-CeO 2 and LMNC-C composites at all discharge rates (C/10 – 5C). The increase of the upper boundary of potentials to 4.8 V after cycling at 5C (U – 2÷4.6 V) promotes the increase of low rate electrochemical capacity of LNMC-CeO 2 -C composite to 220 mAh g −1 . [ABSTRACT FROM AUTHOR]

In the present work, we compare the photocatalytic activity (PCA) of titania samples normalized to the sample weight and specific surface area (SSA), and show a correlation between the PCA of titania catalysts with similar phase compositions and amorphous phase contents. In our studies, we used the commercial samples, P25 Evonik (formerly Degussa), Hombikat UV100, and pre-synthesized mesoporous titania. Catalysts with a significant amorphous content were annealed and processed by partial dissolution in acid and included in the analysis. PCA was measured by methyl orange (MO) photodegradation in an aqueous catalyst suspension under high-pressure Hg bulb illumination and the pH was controlled using phosphate buffer (pH 6.9). The weight percentage of the amorphous phase was determined using reference intensity ratios (RIR) for X-ray diffraction patterns of the titania samples measured with crystalline silicon additives. The reproducibility of the proposed method was demonstrated by measuring the amorphous content in mixtures of the sample and XRD-amorphous titania. The contributions of amorphous titanium oxohydroxides TiO 2−0.5 n (OH) n · x H 2 O and water physically adsorbed to the amorphous phases were distinguished by thermogravimetric analysis. The obtained results show that the PCA of the titania samples decreases with the weight percentage of the amorphous phase, as low as 5% of the PCA of P25 in the case of ω Am (TiO 2 )> 25 %. It was demonstrated that the partial removal of the amorphous phase by annealing or dissolution in nitric acid leads to a significant increase of PCA. [ABSTRACT FROM AUTHOR]

Gold nanorods (AuNRs) stabilized by cetyltrimethylammonium bromide (CTAB) were synthesized and an interaction of catecholamines (CAs) with silver ions in the presence of the obtained AuNRs was studied. The reaction results into formation of core-shell Au@Ag nanorods (Au@AgNRs) and leads to a hypsochromic shift of the long-wave surface plasmon resonance (SPR) band in the absorption spectrum of AuNRs. The influence of a CA structure, excess of CTAB, interaction time, pH, concentration of AuNRs, silver ions and CAs on this interaction was studied. Based on correlation of the NRs spectral characteristics with the concentration of CAs, a method for spectrophotometric determination of dobutamine, epinephrine, norepinephrine and dopamine with detection limits 27, 18, 16 and 13 μg L −1 , respectively, has been developed. The method can be applied to the analysis of medicines. [ABSTRACT FROM AUTHOR]

Novel RNi6Si6 compounds adopt the new CeNi6Si6-type structure for R=La–Ce (tP52, space group P4/nbm N 125-1) and new YNi6Si6-type structure for R=Y, Sm, Gd–Yb (tP52, space group N 117) that are tetragonal derivative of NaZn13-type structure, like LaCo9Si4-type. The CeNi6Si6, GdNi6Si6, TbNi6Si6, DyNi6Si6 and HoNi6Si6 compounds are Curie–Weiss paramagnets down to ~30K, and do not order magnetically down to 5K. However, the inverse paramagnetic susceptibility of LaNi6Si6 does not follow Curie–Weiss law. The DyNi6Si6 shows ferromagnetic-like saturation behaviour at 5K in applied fields of 50kOe, giving rise to a magnetic moment value of 6.5μB/f.u. in 50kOe. The powder neutron diffraction study in zero applied filed indicates square modulated the c-collinear antiferromagnetic ordering of TbNi6Si6 with K=[±1/4, ±1/4, 0] wave vector below ~10K. [ABSTRACT FROM AUTHOR]

• Change of ions tunes the magnetocaloric effects in the range 2–400 K. • 2 Direct MCE with a table-like effect in-between, interesting for Ericsson cycle. • Inverse MCE at low temperatures. • PM-FM transition ruled by long-range magnetic interactions. The structural, magnetic, magnetocaloric (MCE) and thermal properties of seven Fe 2 P-type Dy 6 (Fe,Mn)X 2 (X Sb, Bi, Te) intermetallics (space group P 6 ¯ 2 m , N 189, hP9) have been experimentally studied. They present a paramagnetic to ferromagnetic transition (in the range 129–370 K), followed, as temperature decreases, by a spin-reorientation one (from 52 to 170 K) and a ground magnetic state at 2 K with antiferromagnetic components. This state turns into a ferromagnetic state when a magnetic field is applied. The critical exponents β,γ,δ related to the PM-FM transition point to long range order interactions but in most compounds their values severely deviate from the Mean Field class, presenting an unconventional critical behavior, probably due to magnetocrystalline anisotropies. This magnetic complexity has the consequence that in every intermetallic three MCE effects arise: Two direct magnetocaloric effects (DMCE) with a table-like effect in between (from 40 K to more than 400 K), with moderate values of the magnetic entropy maxima (up to 6.9 J/kgK for μ 0 Δ H = 5 T, with the tableau in-between being around 4 J/kgK, for Dy 6 FeSb 2 and Dy 6 FeSbTe). The calculation of the Thermal Average Entropy Change allows to place the properties of two compounds (Dy 6 FeSb 2 and Dy 6 FeSbTe) close to other rare earth based high entropy alloys described in literature. The seven compounds present a relevant third MCE, inverse, below 25 K, with a value as high as 17.8 J/kgK (μ 0 Δ H = 5 T) for Dy 6 FeSbTe. The maximum of the magnetic entropy change at the Curie temperature has been shown to scale with the critical exponents found and universal curves have been built. Finally, the thermal diffusivities in the range of the DMCE have been measured, with the result that they present good values (between 1 and 3 mm2/s) to be used in real magnetocaloric refrigeration systems. [ABSTRACT FROM AUTHOR]

Abstract: The temperature dependence of electrical conductivity and magnetoconductivity of new type of carbon films composed of nanosize thin graphite-like crystallites were investigated at temperature interval of 4.2–300K and in the magnetic field range of 0–12kG at 4.2K, respectively. The crystallites consist of several (5–50) graphene layers which have predominant orientation perpendicularly to a film surface. At temperature ≤30K the logarithmic conductivity decreases linearly with temperature. The positive magnetoconductivity of the films was observed in a magnetic field directed perpendicularly to the film surface in all intervals of field values. In magnetic field B≥4kG the logarithmic asymptotic of conductivity from magnetic field was observed. That is characteristic of the systems with two-dimensional quantum corrections to magnetoconductivity. In a magnetic field directed along a film surface, the crossover from negative to positive magnetoresistivity is observed at B≥8kG. [Copyright &y& Elsevier]

• Microhotplate catalytic sensors based on anodic alumina supports are prepared. • Methane detection sensitivity reaches 15 mV/vol. % CH 4. • Operando X-ray diffraction and thermogravimetry studies are performed. • Hysteresis in sensitivity correlates with Pd oxides content in the Pd-Pt catalyst. Catalytic pellistor-type sensors are widely used for the analytical detection of flammable/explosive gases. Further improvement of the characteristics of the sensors can be achieved by the development of miniature sensing elements based on planar microhotplates, which allows one to decrease the power consumption substantially. Here we demonstrate the microhotplate catalytic sensors based on anodic aluminium oxide supports for methane detection. The sensor response approaches the value of 15 mV/vol. % CH 4 at the optimal supply voltage. A wide hysteresis in sensor response is observed during the cycling of the supply voltage. This phenomenon is studied under operando conditions using X-ray diffraction and thermogravimetry. The obtained results have a significant impact on the development of optimal working regimes, and the production of planar catalytic sensors on porous supports. [ABSTRACT FROM AUTHOR]

The partial isothermal sections of {Gd, Ho}-Ni-Te and Gd-Co-Te systems (~40–100 ​at. % of rare earth) have been investigated at 1070 ​K by X-ray and electron microprobe analysis. The Y 5 Ni 2 Te 2 -type {Tb, Dy, Ho} 5 Fe 2 Te 2 and {Gd, Tb, Dy, Ho} 5 {Co, Ni} 2 Te 2 (space group Cmcm , No. 63, oC 36), Er 7 Ni 2 Te 2 -type Er 7 Co 2 Te 2 , {Y, Dy, Ho} 7 Ni 2 Te 2 , Ho 7 {Rh, Pd} 2 Te 2 and {Y, Gd} 7 Pt 2 Te 2 (space group Imm 2, No. 44, oI 22), Fe 2 P-type Ho 6 NiTe 2 (space group P -62 m , No. 189, hP 9) and Sc 6 PdTe 2 -type Ho 6 {Rh, Pd}Te 2 and {Y, Gd} 6 PtTe 2 (space group Pnma , No. 62, oP 36) compounds have been established using powder X-ray diffraction studies. Magnetization measurements show that the Y 5 Ni 2 Te 2 -type {Tb, Dy, Ho} 5 Fe 2 Te 2 , {Gd, Tb, Dy} 5 Co 2 Te 2 and {Tb, Ho} 5 Ni 2 Te 2 compounds exhibit a high-temperature ferromagnetic ordering with low-temperature spin-reorientation transition for Tb-, Dy- and Ho-containing compounds. Below Curie temperature, Tb 5 Fe 2 Te 2 , Tb 5 Co 2 Te 2 and Ho 5 Ni 2 Te 2 are soft ferromagnets, while they show hard magnetic properties below spin-reorientation transition. At 2 ​K, Tb 5 Co 2 Te 2 and Tb 5 Fe 2 Te 2 exhibit a coercive field of 35 ​kOe and ~30 ​kOe and the residual magnetization of 17.2 μ B and 22.9 μ B per formula unit, leading to theoretical maximum energy product of ~620 ​kJ/m3 and ~700 ​kJ/m3, respectively. Ho 5 Ni 2 Te 2 reaches a maximum magnetic entropy change of −10.0 ​J/kg⋅K and −9.4 ​J/kg⋅K for a magnetic field change of 0–50 ​kOe ​at 45 ​K and 20 ​K, respectively. Image 1 • Partial {Gd, Ho}-Ni-Te and Gd-Co-Te isothermal sections were obtained at 1070 ​K. • Twenty four new ternary compounds were found in Rare earth-{Fe,Co,Ni,Rh,Pd,Pt}-Te systems. • They are Y 5 Ni 2 Te 2 -, Er 7 Ni 2 Te 2 -, Fe 2 P- and Sc 6 PdTe 2 -type compounds. • Y 5 Ni 2 Te 2 -type {Gd,Tb,Dy,Ho} 5 {Fe,Co,Ni} 2 Te 2 exhibit ferromagnetic type of ordering. • Ho 5 Ni 2 Te 2 shows large MCE, while Tb 5 {Fe, Co} 2 Te 2 are giant LT permanent magnets. [ABSTRACT FROM AUTHOR]

The magnetic and magnetocaloric properties of the intermetallic family (Gd,Tb) 6 (Fe,Mn)Bi 2 have been studied from 2 K to temperatures above the respective Curie temperatures T C. The substitution of Gd by Tb (Gd 6 FeBi 2 , Gd 3 Tb 3 FeBi 2 , Tb 6 FeBi 2) tunes T C in the range 350-250 K and favors the apparition of a metamagnetic transition at very low temperature (below 10 K) from a complex magnetic state to a ferromagnetic one, as well as a spin reorientation transition below T m = 72 K. As a consequence, an important inverse magnetocaloric effect (IMCE) appears below 20 K and an interesting direct magnetocaloric effect (DMCE) appears over a wide temperature span between T C and T m with maxima at those temperatures. The partial substitution of Fe by Mn in Tb 6 Fe 0.5 Mn 0.5 Bi 2 shifts these effects upwards in temperature while expanding the region of the direct magnetocaloric effect between 70 and 400 K. The combination of adjoint IMCE and DMCE as well as the wide span of the latter shows that tuning this family allows to locate the magnetocaloric effect in different regions of interest. The critical behavior of the PM-FM transitions has been studied obtaining the critical exponents α, β, γ, δ and checking that the respective magnetocaloric effects also scale with the critical parameters n and δ. The transition in Gd 6 FeBi 2 belongs to the Heisenberg universality class with deviations due to magnetocrystalline anisotropies; the critical exponents for Gd 3 Tb 3 FeBi 2 (in agreement with the Mean Field model) suggest the presence of long range order magnetic interactions, while Tb 6 FeBi 2 and Tb 6 Fe 0.5 Mn 0.5 Bi 2 present an unconventional critical behavior aligned with long range order interactions. • Gd by Tb substitution tunes T C and improves the magnetocaloric properties. • Tb samples present two main transitions and extended temperature working range. • Adjoint inverse and direct magnetocaloric effects in Td-doped compounds. • Critical exponents α, β, γ, δ found for the PM-FM transition. [ABSTRACT FROM AUTHOR]

Four polycrystaline Fe 2 P-type Ho 6 (Fe,Mn)Bi 2 intermetallic compounds (space group P 6 ‾ 2 m , No. 189, hP 9) have been studied using magnetic techniques in order to explore their ability as magnetocaloric materials, and study the critical behavior of the paramagnetic (PM) to ferromagnetic (FM) transitions to obtain a deeper understanding of the range of the magnetic interactions. The obtained critical exponents β , γ and δ for the four compounds studied (Ho 6 MnBi 2 , Ho 6 FeBi 2 , Ho 6 (Mn 0.5 Fe 0.5)Bi 2 , Ho 6 (Mn 0.75 Fe 0.25)Bi 2) point to long-range order interactions, as they are close to those of the Mean Field Universality class. All of the compounds show relevant magnetocaloric properties over a very broad temperature range, limited by the PM-FM transition and a spin-reorientation one, well separated in all cases. They present very high values of the refrigerant capacities (from 520 J/kg to 709 J/kg at 5 T), good magnetic entropy changes (from 3.4 to 5.7 J/(kgK) at 5 T), and a flat and wide temperature span for the working temperature range (nearly 200 K for Ho 6 MnBi 2 , 80 K for Ho 6 FeBi 2 at 5T). The change in properties with composition proves that the magnetocaloric properties can be tuned in Fe 2 P-type compounds to accommodate different refrigeration applications. Finally, the magnetocaloric scaling laws have been successfully tested and universal curves for the magnetic entropy change have also been obtained in the PM-FM transition region. • Second order FM to PM transition, long-range order interactions involved. • Very high values of the refrigerant capacities from 520 J/kg to 709 J/kg at 5T • Good magnetic entropy changes from 3.4 to 5.7 J/(kgK) at 5T • Flat and wide temperature span for the working temperature range (up to 200 K). • Magnetocaloric scaling laws tested and universal curves obtained. [ABSTRACT FROM AUTHOR]

Application of porous anodic alumina as membranes and templates is restricted by its rapid degradation in acidic and alkaline media. Chemical stability of the anodic alumina could be strongly enhanced by annealing leading to crystallization of as-prepared amorphous material into a mixture of low-temperature Al 2 O 3 polymorphic modifications and then to α-Al 2 O 3 phase. Here an approach to choosing an annealing protocol for crystallization of porous anodic alumina into the corundum phase preserving its starting morphology is suggested. Formation of corundum films with hexagonally-packed 27-nm-diameter channels by multi-step annealing of anodic alumina prepared in 0.3 М sulfuric acid at 25 V is demonstrated. According to electron backscatter diffraction, α-Al 2 O 3 films consist of porous single-crystalline grains with an average size of ~ 5 ÷ 10 μm. Crystallization of α-Al 2 O 3 phase from amorphous anodic alumina results in the enhancement of its chemical stability by two orders of magnitude in comparison with porous films consisting of low-temperature polymorphic modifications of Al 2 O 3. Image 1 • Approach to choosing an annealing protocol for anodic alumina is suggested. • Alpha-alumina films with an ordered arrangement of sub-30 nm pores are obtained. • Coarse-grain structure of porous corundum films is proved by EBSD. • Chemical stability of γ-Al 2 O 3 and α-Al 2 O 3 porous films is compare. [ABSTRACT FROM AUTHOR]