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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 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]

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 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 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]

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]

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]