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Novel ternary intermetallic phase Ce2RuGe was synthesized via arc-melting of the constituents and subsequent annealing at 700°С. Its crystal structure was determined from the powder X-ray diffraction data collected at room temperature. The compound crystallizes in the orthorhombic structure of a new type: space group Pmmn (No. 59), lattice parameters: a = 4.38235(5) A, b = 4.31818(5) A, c = 9.91496(15) A, Z = 2, Pearson symbol oP8. In the fully ordered unit cell of Ce2RuGe, there are two crystallographic positions for Ce atoms, single site with Ru atoms, and single site with Ge atoms, each with the multiplicity of two. The crystal structure is built of infinite zigzag-like chains of the Ru and Ge atoms, propagating along the [010] direction. The essential feature is a very short interatomic distance between the Ce1 atoms and the Ru atoms being equal to 2.226(2) A, while the Ce2–Ru distance is of regular length. This structural property gives rise to distinctive physical behavior of the compound that exhibits the coexistence of valence fluctuations associated with unstable 4f shell of the Ce1 ions and a long-range magnetic ordering that emerges in the Ce2 ions sublattice. As revealed by means of magnetization, heat capacity and electrical resistivity measurements, Ce2RuGe orders antiferromagnetically at TN = 12.0(1) K, and becomes ferromagnetic below TC = 8.5(3) K.

The crystal structure of the novel Al-rich intermetallic phase Ce4Pt9Al13 was determined from single-crystal X-ray diffraction data and confirmed by powder X-ray diffraction. The compound crystallizes with its own structure type, which is a “site exchange” variant of the Ho4Ir13Ge9-type (Pearson symbol oP52, space group Pmmn, No. 59, Z = 2, lattice parameters: a = 4.1826(1) A, b = 11.4424(3) A, c = 19.8475(5) A, V = 949.88(7) A3). The magnetic properties of Ce4Pt9Al13 were determined in the temperature range 1.72–400 K. Down to the lowest temperatures studied, the compound shows a Curie-Weiss paramagnetic behavior with strong crystalline electric field contribution observed below about 200 K. The electrical conductivity in Ce4Pt9Al13 has metallic character, and at low temperatures it is governed by an interplay of strong crystal field and Kondo interactions.

A novel ternary intermetallic germanide CeIrGe 2 has been studied by means of x-ray diffraction, magnetization, specific heat and electrical resistivity measurements, performed in wide ranges of temperature and external magnetic fields. The compound crystallizes in an orthorhombic structure of the CeNiSi 2 -type (space group Cmcm ). It exhibits a Kondo lattice behavior and orders antiferromagnetically at 4 K.

The novel cerium germanide Ce2IrGe3 was studied by means of x-ray diffraction, magnetic, electrical transport and heat capacity measurements. The compound was found to crystallize with slightly disordered hexagonal structure of Ce2CoSi3-type. The experimental results revealed that Ce2IrGe3 is a ferromagnetic-like Kondo lattice that orders at T C = 4 K .

The new ternary intermetallic with high content of germanium, CeRuGe 5 , was found in the course of reinvestigation of the Ce-Ru-Ge system at 700 °C. The compound crystallizes in the tetragonal structure of new type (space group I 4/ mcm ) with the unit cell parameters: a = 6.1414(6) A, c = 13.751(3) A, Z = 4, Pearson symbol tI 28. The structure of CeRuGe 5 can be presented as [CeGe 3 ] and [RuGe 2 ] slabs alternating along the tetragonal c -axis. It is shown that the new structure of CeRuGe 5 and the known before structure of Sm 2 Ru 5 Ga 9 are derivatives from the common prototype – HoCoGa 5 . By means of magnetic, heat capacity and electrical transport measurements, the novel compound CeRuGe 5 was established to be a metallic Curie-Weiss paramagnet due to stable 4 f 1 electronic configuration of trivalent Ce ions. No intrinsic long-range magnetic ordering was found down to 1.7 K.

Phase relations in the ternary system Ce–Ir–Si have been established and the isothermal section at 950 °C was constructed based on X-ray powder diffraction, scanning electron microscopy, and electron probe microanalysis techniques on 83 alloys, which were prepared by arc melting under argon or powder reaction sintering. Among the 15 ternary compounds observed at 950 °C 8 phases have been reported earlier. Based on powder X-ray diffraction data the crystal structures for 6 new ternary phases were assigned to known structure types: τ6 – Ce3IrSi3 (Ta3B4-type), τ8 – Ce3Ir4Si4 (U3Ni4Si4-type), τ10 – Ce6Ir30Si19 (Sc6Co30Si19-type), τ12 – Ce2Ir12Si7 (Ho2Rh12As7-type), τ13 – Ce3Ir2−xSi2+x (Sm3Ir2Si2-type), and τ14 – Ce3Ir3Si2 (Ce3Rh3Si2-type). For another new compound τ1 – Ce4Ir27Si69 (at.%), which has homogeneity region along 27 at.% of Ir, the reflections were indexed in hexagonal lattice symmetry with cell parameters close to high-temperature IrSi3−x phase.

A novel ternary compound Ce 3 RuSn 6 was synthesized as a single phase polycrystalline alloy. Its crystal structure was solved by direct methods and refined from the single crystal X-ray diffraction data down to R1 = 0.038 for 1021 independent reflections with I > 2σ(I) and 36 variable parameters. The compound crystallizes with an orthorhombic unit cell of the Yb 3 CoSn 6 type (space group Cmcm , lattice parameters: a = 4.6744 (4), b = 16.8542 (15), c = 13.3227 (12) A), in which Ce atoms occupy two independent crystallographic sites. Physical behavior in Ce 3 RuSn 6 was studied by means of magnetic susceptibility, electrical resistivity and heat capacity measurements, performed down to 0.4 K in magnetic fields up to 9 T. The compound exhibits ferromagnetic ordering below T C = 3 K. Its thermodynamic and electrical transport properties in the paramagnetic and ordered states are strongly influenced by Kondo effect with the characteristic temperature very close to T C .

The aluminides CePd2Al2, CePd3Al3, and CePd4Al4 were synthesized and their properties studied by X-ray diffraction, magnetic, heat capacity, and electrical transport measurements. The crystal structures of CePd2Al2 and CePd4Al4 were determined and refined from the single-crystal X-ray diffraction data, while that of CePd3Al3 was designed by the trial-and-error method on the basis of crystal chemistry considerations and refined by the Rietveld method from the X-ray powder diffraction data. All three compounds were found to crystallize in the tetragonal space group P4/nmm with Z = 2. The lattice parameters of CePd2Al2 are a = 4.3974(9) Å and c = 9.871(4) Å. Those of CePd3Al3 are a = 4.3045(7) Å and c = 13.4426(18) Å, while those of CePd4Al4 are a = 4.325(2) Å and c = 16.230(5) Å. The structures represent a new homologous series built of structural units of the CaBe2Ge2- and CsCl-type. The three compounds were established to order antiferromagnetically at 2.5(1) K, 3.5(1) K, and 2.6(1) K for CePd2Al2, CePd3Al3, and CePd4Al4, respectively. All of them are Kondo lattices with the characteristic energy scale of 3-7 K.

The formation of novel ternary cerium germanide with the chemical composition Ce33.3Ir22.2Ge44.5 (at.%) was established. As derived from powder X-ray diffraction data, the compound crystallizes with two polymorphic modifications. The high-temperature modification, established for as-cast alloy, possesses a tetragonal ThSi2-type structure and can be named as Ce(IrxGe1-x)2, x = 0.32. The low-temperature modification forms in the course of heat treatment at 1073 K, crystallizes with an orthorhombic structure of its own type and can be labeled as Ce3Ir2-xGe4+x, x = 0.02. Both structures belong to the AlB2 structural family and are closely related to each other. In both modifications, statistical mixtures of Ir and Ge atoms occupy same crystallographic sites. As found by means of magnetization measurements, the two structural variants of Ce33.3Ir22.2Ge44.5 (at.%) exhibit very similar magnetic properties. Both polymorphs are Curie-Weiss paramagnets with strong crystalline electric field features observed at low temperatures.

Magnetic ordering in solid solutions of Cex(Gd,Pr,Nd,La)1-xNi is studied by measuring the DC magnetization and the AC susceptibility in the temperature range of 1.8–300 K. The valence state of ceriumions in Cex(Gd,Pr,Nd,La)1-xNi quasibinary systems is studied based on X-ray absorption spectra measured at synchrotron-radiation sources in the temperature range of 5–300 K. It is shown that chemical pressure and lowering the temperature help heighten the degree of delocalization of the 4f electrons of cerium in Cex(Gd, Nd, Pr)1-xNi systems. It is found that the substitution of magnetic ions (Gd, Pr, and Nd) with cerium results in significantly weaker magnetic-ordering suppression than the substitution of these ions with lanthanum at equal concentrations. The obtained data reveal the strong influence of cerium electrons on localized magnetism in the studied compounds. This effect is most probably associated with the contribution of partially delocalized 4f electrons of cerium to the exchange interaction.

The new title compound is synthesized by repeated arc melting of stoichiometric mixtures of the elements.

The crystal structure of Dy 2 PdGe 6 was studied by X-ray diffraction on single crystal. Space group Cmca (No. 64), a = 8.1337(16), b = 8.0208(16), c = 21.441(4) A, V = 1398.8 A 3 , Z = 8, 1259 unique reflections with I > 2 σ ( I 0 ) in refinement (2 Θ max = 75.81°), down to R 1 = 0.029, w R 2 = 0.071. The title compound represents an ordered derivative from the Ce 2 GaGe 6 -type. The crystal structure can be presented as a sequence of the AlB 2 -type slabs, quadrangular antiprisms slabs, and distorted αPo-type slabs along the c direction. The atomic order in Dy 2 PdGe 6 derived from the single crystal data was confirmed by X-ray powder diffraction with cell parameters a = 8.1348(6), b = 8.0145(5), c = 21.4396(14) A.

The crystal structure of the novel compound Ce 3 Rh 5 Si was solved by means of powder diffraction pattern analysis using the charge-flipping method. The refinements yielded the space group Pnma and the orthorhombic unit cell parameters: a = 1.52632(2) nm, b = 0.55092(1) nm, and c = 0.75302(1) nm. A characteristic feature of the crystal structure of Ce 3 Rh 5 Si are vertex-sharing [Rh 4 ] and [Rh 3 Si] tetrahedra, which form a three-dimensional framework with Ce atoms located inside truncated tetrahedral voids. The structure exhibits close relationship with those of CeRh 2 (MgCu 2 -type) and Ce 2 Rh 3 Si (Y 2 Rh 3 Si-type). Magnetic and electrical resistivity measurements of Ce 3 Rh 5 Si were performed down to 2 K. The compound was characterized as a Pauli paramagnet with metallic character of the electrical conductivity.

Five novel cerium-based ternaries Ce2Rh3.1Si0.9 ,C e 4Rh12Si, Ce8Rh21.9Si3.1, CeRh1.82Si0.18 and CeRh3Si0.125 were studied by means of magnetic susceptibility and electrical resistivity measurements. All these phases were found to be Pauli paramagnets with metallic type of electrical conductivity.

We have studied chemical interaction of the intermetallic compound NdRh3 with hydrogen at pressures of up to 0.2 GPa. The structural changes in the intermetallic matrix in different stages of the hydrogenation process have been followed using synchrotron X-ray diffraction. The results demonstrate that hydrogen absorption leads to an irreversible change in lattice symmetry from hexagonal to cubic.

Two series of intermetallic alloys, RT2Si and RTSi2, have been synthesized from stoichiometric compositions. The crystal structures of EuPt1+xSi2−x (CeNiSi2-type), CeIr2Si (new structure type), YbPd2Si and YbPt2Si (both YPd2Si-type) have been elucidated from X-ray single crystal CCD data, which were confirmed by XPD experiments. The crystal structures of LaRh2Si and LaIr2Si (CeIr2Si-type), {La,Ce,Pr,Nd}AgSi2 (all TbFeSi2-type), and EuPt2Si (inverse CeNiSi2-type) were characterized by XPD data. RT2Si/RTSi2 compounds were neither detected in as-cast alloys Sc25Pt50Si25, Eu25Os25Si50 and Eu25Rh25Si50 nor after annealing at 900 °C. Instead, X-ray single crystal data prompted Eu2Os3Si5 (Sc2Fe3Si5-type) and EuRh2+xSi2−x (x=0.04, ThCr2Si2-type) as well as a new structure type for Sc2Pt3Si2 (own type).

Phase relations in the ternary system Ce–Pd–Si have been established for the isothermal section at 8001C based on X-ray powder diffraction and EMPA techniques on about 130 alloys, which were prepared by arc-melting under argon or powder reaction sintering. Eighteen ternary compounds have been observed to participate in the phase equilibria at 8001C. Atom order was determined by direct methods from X-ray single-crystal counter data for the crystal structures of t8—Ce3Pd4Si4 (U3Ni4Si4type, Immm; a ¼ 0.41618(1), b ¼ 0.42640(1), c ¼ 2.45744(7) nm), t16—Ce2Pd14Si (own structure type, P4/nmm; a ¼ 0.88832(2), c ¼ 0.69600(2) nm) and also for t18—CePd1� xSix (x ¼ 0.07; FeB-type, Pnma; a ¼ 0.74422(5), b ¼ 0.45548(3), c ¼ 0.58569(4) nm). Rietveld refinements established the atom arrangement in the structures of t5—Ce3PdSi3 (Ba3Al2Ge2-type, Immm; a ¼ 0.41207(1), b ¼ 0.43026(1), c ¼ 1.84069(4) nm) and t13—Ce3� xPd20+xSi6 (0rxr1, Co 20Al3B6-type, Fm3 ¯ m; a ¼ 1.21527(2) nm). The ternary compound Ce2Pd3Si3 (structure-type Ce2Rh1.35Ge4.65, Pmmn; a ¼ 0.42040(1), b ¼ 0.42247(1), c ¼ 1.72444(3) nm) was detected as a high-temperature compound, however, does not participate in the equilibria at 8001C. Phase equilibria in Ce–Pd–Si are characterized by the absence of cerium solubility in palladium silicides. Mutual solubility among cerium silicides and cerium–palladium compounds are significant whereby random substitution of the almost equally sized atom species palladium and silicon is reflected in extended homogeneous regions at constant Cecontent such as for t2—Ce(PdxSi1� x)2 (AlB2-derivative type), t6—Ce(PdxSi1� x)2 (ThSi2-type) and t7—CePd2� xSi2+x. The crystal structures of compounds t4—Ce� 8Pd� 46Si� 46, t12—Ce� 29Pd� 49Si� 22, t15—Ce� 22Pd� 67Si� 11, t17—Ce� 5Pd� 77Si� 18 and t18—CePd1� xSix (x� 0.1) are still unknown.

The crystal structures of ternary compounds RPt3−xSi1−y(R=Y, Tb, Dy, Ho, Er, Tm, Yb) have been elucidated from X-ray single crystal CCD data. All compounds are isotypic and crystallize in the tetragonal space group P4/mbm. The general formula RPt3−xSi1−y arises from defects: x≈0.20, y≈0.14. The crystal structure of RPt3−xSi1−y can be considered as a packing of four types of building blocks which derive from the CePt3B-type unit cell by various degrees of distortion and Pt, Si-defects.

Phase relations in the ternary system Ce–Pt–Si have been established for the isothermal section at 800 °C based on X-ray powder diffraction, metallography, scanning electron microscopy (SEM) and electron probe microanalysis (EPMA) techniques on about 120 alloys, which were prepared by various methods employing arc-melting under argon or powder reaction sintering. Nineteen ternary compounds were observed. Atom order in the crystal structures of τ18-Ce5(Pt,Si)4 (Pnma; a=0.77223(3) nm, b=1.53279(8) nm c=0.80054(5) nm), τ3-Ce2Pt7Si4 (Pnma; a=1.96335(8) nm, b=0.40361(4) nm, c=1.12240(6) nm) and τ10-CePtSi2 (Cmcm; a=0.42943(2) nm, b=1.67357(5) nm, c=0.42372(2) nm) was determined by direct methods from X-ray single-crystal CCD data and found to be isotypic with the Sm5Ge4-type, the Ce2Pt7Ge4-type and the CeNiSi2-type, respectively. Rietveld refinements established the atom arrangement in the structures of Pt3Si (Pt3Ge-type, C2/m, a=0.7724(2) nm, b=0.7767(2) nm, c=0.5390(2) nm, β=133.86(2)°), τ16-Ce3Pt5Si (Ce3Pd5Si-type, Imma, a=0.74025(8) nm, b=1.2951(2) nm, c=0.7508(1) nm) and τ17-Ce3PtSi3 (Ba3Al2Ge2-type, Immm, a=0.41065(5) nm, b=0.43221(5) nm, c=1.8375(3) nm). Phase equilibria in Ce–Pt–Si are characterised by the absence of cerium solubility in platinum silicides. Cerium silicides and cerium platinides, however, dissolve significant amounts of the third component, whereby random substitution of the almost equally sized atom species platinum and silicon is reflected in extended homogeneous regions at constant Ce content such as for τ13-Ce(PtxSi1−x)2, τ6-Ce2Pt3+xSi5−x or τ7-CePt2−xSi2+x.

Cerium ruthenium indides, Ce2Ru2In3 and Ce3Ru2In2, were synthesized from the pure elements by arc-melting. Both structures present a site exchange variant of a new structure type with different occupation of one crystallographic site: space group Pnma, Z = 4, oP28, with cell parameters a = 17.7054(4) A, b = 4.7144(1) A, c = 7.4072(1) A for Ce2Ru2In3, and a = 17.394(2) A, b = 4.9073(6) A, c = 7.669(1) A for Ce3Ru2In2 at room temperature. In the structures there are eight extremely short Ce–Ru contacts per unit cell: Ce1–Ru1 = 2.3225(8) A, Ce1–Ru2 = 2.3681(8) A in Ce2Ru2In3, and Ce1–Ru1 = 2.2345(9) A, Ce3–Ru2 = 2.2811(9) A in Ce3Ru2In2. Such contacts cause considerable distortion of coordination polyhedra of all atoms and reduce cell parameter a by 1 A when compared to the parent NdRh2Sn4 structure.

The dynamic magnetic response of the intermediate-valence compound EuCu2Si2 has been studied using inelastic neutron scattering. At low temperatures, strong renormalization of the 7F0 → 7F1 spin-orbit transition energy is detected; it is likely to be related to partial delocalization of the f electrons of Eu. An increase in the temperature increases the valence instability of europium and results in further changes in the magnetic excitation spectrum parameters and the appearance of an intense quasi-elastic component.

Polycrystalline Ce2Ru2Al is prepared by arc melting of the elements and subsequent annealing (evacuated quartz ampoules, 823 K, 30 d).

CePd2Al2 (I), CePd3Al3 (II), CePd3.04Al2.96, CePd4Al4 (III), and CePd4.06Al3.94 are prepared by arc melting of the elements followed by annealing (evacuated quartz tubes, 1070 K, ≥ 30 d).

The crystal structure of a new low-temperature modification of CePdAl was determined from single-crystal x-ray data: CePdAl-type; space group Pmmn (No. 59), Z = 14, oP42, a = 0.426 07 nm, b = 2.887 58 nm, c = 0.721 90 nm; RF = 0.048. Physical properties of orthorhombic CePdAl are governed by a mutual balance of the RKKY interaction, the Kondo effect and crystalline electric field splitting, resulting in antiferromagnetic ordering below ≈2.5 K. Electronic transport is reminiscent of a textbook-like Kondo lattice, which comes along with a significant negative magnetoresistance of more than 50% at low temperatures. Although geometrical frustration is absent when compared to the hexagonal modification of CePdAl, the ordering temperature TN is even smaller. A possible cause is enhanced Kondo interactions.

The ternary intermetallic compounds Ce 0.67 Pt 2 Al 5 ( I ) and Ce 1.33 Pt 3 Al 8 ( II ) were synthesized in the Ce–Pt–Al system by the reaction of elemental Ce, Pt, and Al in an arc furnace under an argon atmosphere. The crystal structures of I and II were determined from single-crystal X-ray diffraction data. The crystals are characterized by the following unit cell parameters: a = 4.3105(18) A, c = 16.494(5) A, space group P 6 3 / mmc , Z = 2 ( I ) and a = 4.361(2) A, c = 39.00(2) A, space group R 3 ¯ m , Z = 6 ( II ). Both compounds have structures with different packing of layers.

Novel representatives REPt3Si (RE = La, Pr, Nd, Sm and Gd) of the CePt3B type have been synthesized and characterized by means of Rietveld x-ray powder diffraction. Measurements of the magnetic susceptibility, isothermal magnetization, temperature dependent specific heat as well as temperature and field dependent resistivity were employed to derive basic information on the low temperature behaviour. Long range antiferromagnetic order from 2.2 K (CePt3Si) to 15.1 K (GdPt3Si) was observed. PrPt3Si, however, is non-magnetic, at least down to 400 mK, as a consequence of crystalline electric field splitting of the non-Kramers ion Pr3+ in tetragonal symmetry. Whilst the ordering temperature of SmPt3Si appears to be almost unaffected in external fields up to 12 T, magnetic order in GdPt3Si, although twice as high as for the Sm homologue, is easily suppressed by external magnetic fields due to the absence of anisotropy.

The electronic and magnetic properties of the ternary cerium compounds Ce 2 PdGe 6 and Ce 2 PtGe 6 are reported within the context of measurements of electrical resistivity, magnetoresistivity, and magnetic susceptibility. Ce 2 PdGe 6 orders magnetically at T N = 11.5 K , and Ce 2 PtGe 6 at T N = 9.9 K . In the ordered region, the magnetization as well as the magnetoresistance reveal anomalous behaviour for both compounds, which are ascribed to metamagnetic transitions into a field-induced ferromagnetic state.

The interaction of the components in the Ce–Pt–Si system at 600 °C was investigated over the whole concentration range by X-ray powder and single crystal diffraction, DTA, and electron probe X-ray analysis. There are nine ternary compounds in the Ce–Pt–Si system. The crystal structures of eight of them were determined.

The crystal and magnetic structures of U(Pd 1− x M x ) 2 Ge 2 compounds with M=Fe, Co, Ru are studied by neutron powder diffraction and μSR. The effects of M doping and external applied pressure on the crystal and magnetic structures are compared. We find that even at small M-doping level the magnetic structure drastically changes, while the values of the lattice parameters and interatomic distances change only slightly. In contrast, a high external pressure modifies the crystal structure more significantly, while the magnetic structure remains the same. These observations allow us to conclude that the drastic changes of magnetic structure of U(Pd 1− x M x ) 2 Ge 2 compounds with increased M doping could result from modifications of the RKKY indirect exchange interactions owing to a variation of conduction-electron number per U atom, rather than from lattice contraction.

The crystal structure of the U(Pd1−xFex)2Ge2 compounds with Fe content x = 0– 0.03 and the crystal and magnetic structure of U(Pd0.98Fe0.02)2Ge2 at high external pressures up to 4.5 GPa were studied by means of powder neutron diffraction in the temperature range 1.5–300 K. With increasing Fe content the values of the lattice parameters and interatomic distances change only slightly, but it is known from previous experiments that the magnetic structure changes drastically for x ≥ 0.015. In contrast to this, high external pressure modifies the crystal structure more significantly while the magnetic structure remains unchanged. The results obtained allow one to infer that drastic changes in the magnetic structure of the U(Pd1−xFex)2Ge2 compounds with increasing Fe content are a consequence of modification of the RKKY-type (RKKY standing for Ruderman, Kittel, Kasuya and Yosida) indirect exchange interaction due to the variation of the number of conduction electrons per U atom rather than a result of lattice contraction.

The magnetic ordering of the ternary intermetallic compound U(Pd1-xFex)2Ge2 (x = 0.01, 0.02) was studied by µSR in the temperature range T = 15-300 K. The low temperature state changes from the modulated longitudinal spin density wave LSDW (x = 0.01) with a propagation vector k = [0 0 3/4] (TN = 140 K) to a simple antiferromagnetic structure AF (x = 0.02) with k = [0 0 1] (TN = 140 K). In the AF phase (sample with x = 0.02) the uranium magnetic moment shows a monotonic temperature dependence. In the LSDW phase with k = [0 0 3/4] (sample with x = 0.01) the magnetic moments of uranium atoms located in two magnetically nonequivalent positions (0 0 0) and (0 0 1) have different temperature dependences. One moment assumes a maximum at Tm1 = 50 K, while the other one does not display any peculiarities. The results are discussed within a model of the superposition of a square and sine modulation and are compared with neutron diffraction data. The observed peculiar temperature behaviour of the moments is connected with the temperature variation of the initial phase of the LSDW modulation by Δ = 0.2 rad.

The low-temperature state of U ( Pd 1−x Fe x ) 2 Ge 2 (x=0.01, 0.02) is transformed from simple anti-ferromagnetism AF (x=0.02) with a propagation vector k =[0 0 1] to the modulated longitudinal spin density wave LSDW (x=0.01) with k =[0 0 3 4 ] . ZF-μSR showed that in the sample with x=0.01 the magnetic moments of uranium atoms in two magnetically nonequivalent positions (0 0 0) and (0 0 1) have different temperature dependencies. The results are discussed in the model of a superposition of square and sine shape of modulation in comparison with neutron diffraction data. It is shown, that the observed temperature behavior of moments can be connected with the temperature variation of the initial phase of LSDW modulation.

Phase equilibria in the Sm–{Pd,Pt}–{Si,Ge} systems were studied at 870 K, and intermetallic compounds containing 20 at.% Sm were characterized by physical–chemical analysis methods.

A novel ternary compound has been found at the 1:2:1 position among the Yb–Pd–Si phases, where YbPd 2 Si crystallises in the ordered Fe 3 C -structure. YbPd 2 Si is characterised by Kondo lattice features at higher temperatures and, presumably, antiferromagnetism at 2.1 K. A quasi-quartet crystal field ground state governs the physics at low temperature.

Physico-chemical analysis techniques, including X-ray phase analysis and differential thermal analysis were employed for the characterisation of compounds including their melting temperature. The melting temperature of 23 RT2X2 compounds belonging to the CeGa2Al2 structure has been measured. The melting temperature of 19 RTX2 compounds belonging to the CeNiSi2 structure has been measured (LaCoSi2, LaNiSi2, CeFeSi2, CeCoSi2, CeNiSi2, SmCoSi2, SmNiSi2, ErCoSi2, ErNiSi2, TmCoSi2, TmNiSi2, LaCoGe2, LaNiGe2, CeFeGe2, CeCoGe2, CeNiGe2, SmFeGe2, SmCoGe2, SmNiGe2). It is established, that the new ternary compound SmCoSi2 belongs to the CeNiSi2 structure type (group Cmcm, a=0.4088(1) nm, b=1.6320(3) nm, c=0.4008(1) nm).

Copyright (c) 1997 Elsevier Science S.A. All rights reserved. A novel ternary compound Ce 3 Pt 23 Ge 11 crystallises in a new structure type with space group F 3m and a=1.71833(9) nm. Here we present the results of magnetic, electrical and specific heat measurements, obtained on the single crystal and polycrystalline samples. This compound is a metal with normal Ce 3+ magnetic behaviour. Although the specific heat at low temperatures rises rapidly to a large value of 2.5 J/Ce-mol K at 0.38 K, we have not detected any phase transition down to this temperature. Only in the temperature range 0.1-1 K a small decrease in the resistivity value can be detected with an inflection point at approximately 0.3 K.

The title compound is unintentionally obtained by arc melting of the elements in a ratio pertaining to YbPtSi2 with 3 wt.% excess of Yb due to its high volatility.The crystal structure of the novel intermetallic is determined by single crystal XRD (space group P21/m, Z = 2) and found to be a disordered variant of the Y3Pt4Ge6 type characterized by the intergrowth of slabs cut from the ThCr2Si2 and YIrGe2 types of structures.

The crystal structure of the new ternary silicide CePt 3 Si [space group P 4 mm , a =4.072(1) A, c =5.442(2) A, Z =1, V =90.25(5) A 3 , R =0.0437 for 153 structure factors] was determined from single-crystal X-ray diffraction. The compound belongs to the CePt 3 B structure type of intermetallic compounds.

The crystal structure of the compound CeRh 2 Si was studied by X-ray single crystal diffraction methods and refined to R F =0.038: space group Cmcm , a =4.0413(9) A, b =17.730(3) A, c =4.0675(9) A, V =291.45(10) A 3 , Z =4. The structure belongs to a structure type that can be considered as a site exchange variant of the known CeNiSi 2 structure type (CeSiRh 2 ) with slightly different axial ratios.

The crystal structure of the intermetallic compound Ce 3 Ru 4 Al 12 has been studied. The experiment was carried out using the X-ray single crystal diffraction technique. It was established that the structure belongs to the Gd 3 Ru 4 Al 12 structure type, which is related to the EuMg 5.2 type. Ce 3 Ru 4 Al 12 has the space group P6 3 /mmc, a = 8.8652(10) A, c = 9.5700(2) A, V = 651.4(2) A 3 , and Z = 2.

The new title compound is prepared by arc melting of the elements and its crystal structure is determined by powder XRD.

The crystal structure of the new ternary compound, Ce 3 Pt 23 Si 11 , was determined by X-ray analysis of a single crystal (Enraf-Nonius CAD-4 diffractometer, Mo Kα radiation, 585 independent reflections, R =0.0487). The Ce atoms have only one crystallographic position with a very rare tetragonal prism coordination polyhedron.

The title compound is prepared by arc melting of the elements and characterized by powder XRD and magnetic, electrical resistivity, and heat capacity measurements.

The new compounds CeRh1.82Si0.18, CeRh3Si0.125, Ce2Rh3.1Si0.9, Ce4Rh12Si, and Ce8Rh21.9Si3.1 are prepared by arc melting of the elements followed by annealing at 950 °C for two weeks.

The crystal structure of the compound Ce3Pt23Ge11 has been determined by X-ray analysis of a single crystal (Enraf-Nonius CAD-4 autodiffractometer, Mo Kα radiation, 276 independent reflections, R-factor 0.0735 in isotropic approximation). This structure has been found to belong to a new structural type: space group F 4 3m, a = 17.1833(9) A , Z = 8 . The coordination polyhedra of the cerium atoms are compressed cubes, those of platinum have eight or 10 apexes and those of germanium are either trigonal prisms with an additional atom or cubes. The magnetic properties of Ce3Pt23Ge11 at low temperatures (4–100 K) were investigated. A diffuse magnetic phase transition at around 10 K was detected.

The crystal structure of the compound Ce 7 Pd 4 Ge 2 has been determined by X-ray analysis of a single crystal (Dartch autodiffractometer, Mo Kα radiation, 1116 independent reflections, reliability factor R = 0.0491 in the anisotropic approximation). This structure has been found to belong to a new structural type: space group P2 1 /n, a = 9.315(2) A , b = 12.277(7) A , c = 12.698(3) A , β = 114.31(2)° , Z = 4. The coordination polyhedra of the cerium atoms have 15 and 17 apexes, those of palladium are trigonal prisms with three additional atoms and a tetragonal antiprism with one additional atom, and those of germanium are trigonal prisms with three additional atoms.

The crystal structure of the new compound Ce 3 Pd 5 Si was investigated by X-ray single crystal diffraction method. The compound crystallizes in a new structure type, space group Imma Z =4, a =1.3027(4) nm, b =0.7377(4) nm, c =0.7580(4) nm.

The interaction of the components in the Er–Co–Pd system at 600°C was investigated over the composition range 0–50 at% of erbium by X-ray powder, metallography, electron probe microanalysis (EPMA), DTA and SEM. The isothermal section at 600°C was determined based on these results.

The intermetallic compound CePd5Ge3 has been studied by means of magnetisation, magnetic susceptibility, electrical resistivity and specific heat measurements. The results indicate the presence of stable Ce3+ ions, but nevertheless the compound does not order magnetically down to 2 K. However, some hints on magnetic ordering below 2 K may be deduced from anomalous low temperature behaviour of the magnetisation, resistivity and specific heat. The properties of CePd5Ge3 are discussed in terms of possible Kondo interactions.