Pseudoternary Solid Solution Research Articles

Ductile P-Type AgCu(Se,S,Te) Thermoelectric Materials.

Ductile inorganic thermoelectric (TE) materials open a new approach to develop high-performance flexible TE devices. N-type Ag2(S,Se,Te) and p-type AgCu(Se,S,Te) pseudoternary solid solutions are two typical categories of ductile inorganic TE materials reported so far. Comparing with the Ag2(S,Se,Te) pseudoternary solid solutions, the phase composition, crystal structure, and physical properties of AgCu(Se,S,Te) pseudoternary solid solutions are more complex, but their relationships are still ambiguous now. In this work, via systematically investigating the phase composition, crystal structure, mechanical, and TE properties of about 60 AgCu(Se,S,Te) pseudoternary solid solutions, the comprehensive composition-structure-property phase diagrams of the AgCuSe-AgCuS-AgCuTe pseudoternary system is constructed. By mapping the complex phases, the "ductile-brittle" and "n-p" transition boundaries are determined and the composition ranges with high TE performance and inherent ductility are illustrated. On this basis, high performance p-type ductile TE materials are obtained, with a maximum zT of 0.81 at 340 K. Finally, flexible in-plane TE devices are prepared by using the AgCu(Se,S,Te)-based ductile TE materials, showing high output performance that is superior to those of organic and inorganic-organic hybrid flexible devices.

Flexible thermoelectrics based on ductile semiconductors.

Flexible thermoelectrics provide a different solution for developing portable and sustainable flexible power supplies. The discovery of silver sulfide-based ductile semiconductors has driven a shift in the potential for flexible thermoelectrics, but the lack of good p-type ductile thermoelectric materials has restricted the reality of fabricating conventional cross-plane π-shaped flexible devices. We report a series of high-performance p-type ductile thermoelectric materials based on the composition-performance phase diagram in AgCu(Se,S,Te) pseudoternary solid solutions, with high figure-of-merit values (0.45 at 300 kelvin and 0.68 at 340 kelvin) compared with other flexible thermoelectric materials. We further demonstrate thin and flexible π-shaped devices with a maximum normalized power density that reaches 30 μW cm-2 K-2. This output is promising for the use of flexible thermoelectrics in wearable electronics.

Interplay between crystal field splitting and Kondo effect in CeNi9Ge4−xSix

The pseudo-ternary solid solution CeNi9Ge4−xSix (0 ≤ x ≤ 4) has been investigated by means of x-ray diffraction, magnetic susceptibility, specific heat, electrical resistivity, thermopower and inelastic neutron scattering studies. The isoelectronic substitution of germanium by silicon atoms causes a dramatic change of the relative strength of competing Kondo, RKKY and crystal field (CF) energy scales. The strongest effect is the continuous elevation of the Kondo temperature TK from approximately 3.5 K for CeNi9Ge4 to about 70 K for CeNi9Si4. This increase of the Kondo temperature is attended by a change of the CF level scheme of the Ce ions. The interplay of the different energy scales results in an incipient reduction of the ground state degeneracy from an effectively fourfold degenerate non-magnetic Kondo ground state with unusual non-Fermi-liquid features of CeNi9Ge4 to a lower one, followed by an increase towards a sixfold, fully degenerate ground state multiplet in CeNi9Si4 (TK ∼ ΔCF).

New real ternary and pseudoternary phases in the Li–Au–In system

Two real ternary lithium gold indides LiAu 2In and Li 280Au 22In 130 (Li 0.65Au 0.05In 0.30) were found in the Li–Au–In system. They are isostructural to the respective Ag-alloys. LiAu 2In crystallizes in the MnCu 2Al-type structure ( Fm-3 m, Heusler phase, a=6.4982(8) Å, based on single crystal XRD-data) and Li 280Au 22In 130 in the Li 278Ag 40In 114-type structure ( F-43 m, a=19.9970(2) Å, based on powder XRD-data). The analogy of the two ternary systems Li–Au–In and Li–Ag–In is additionally reaffirmed by the wide homogeneity range of the pseudoternary solid solution with NaTl-type structure (Zintl phase),which expands not only in the direction of the quasibinary cut Li(Au x In 1− x ) with 0≤ x≤0.5, but also into the directions of both higher and lower Li-concentrations.

Advantages of Simultaneous Substitution of Co in Li[Ni[sub 1∕3]Mn[sub 1∕3]Co[sub 1∕3]]O[sub 2] by Ni and Al

Ni and Al can be substituted for Co in Li[Ni 1/3 Mn 1/3 Co 1/3 ]O 2 by increasing y and z in x LiNi 1/3 Mn 1/3 Co 1/3 O 2 -y LiNi 2/3 Mn 1/3 O 2-z LiNi 1/3 Mn 1/3 Al 1/3 O 2 (x + y + z = 1) pseudoternary solid solution systems. Additions of Al improve the thermal stability of the charged positive electrode material, at a cost of capacity reduction, which can be at least partially recovered by the addition of Ni. The composition Li[Ni (1/3+0.07) Mn 1/3 CO (1/3-0.2) Al 0.13 ]O 2 (x = 0.4, y = 0.2, z = 0.4) shows excellent thermal stability compared to Li[Ni 1/3 Mn 1/3 Co 1/3 ]O 2 , but similar specific capacity. The samples were synthesized via a coprecipitation-based synthetic method to prepare a mixed hydroxide precursor, followed by sintering with a Li salt. Such materials may find application in large-size Li-ion batteries targeted for vehicle applications.

Kondo and magnetic ordering anomalies in Ce 2−xR xPtSi 3 (R=La, Y)

The compound Ce 2PtSi 3 crystallizing in the AlB 2-derived hexagonal structure has been known to undergo magnetic ordering around ( T 0=) 5.5 K. We have investigated the influence of positive and negative chemical pressure on the Kondo effect and T 0 by studying Y and La substituted pseudo-ternary solid solutions Ce 2− x R x PtSi 3 (R= La, Y) by AC and DC magnetic susceptibility, and heat capacity measurements. We find that the dilution of Ce sub-lattice by Y substitution is less effective in reducing T 0 when compared with La substituted series. The Kondo temperature as inferred from paramagnetic Curie temperature undergoes an increase with increasing La content, rather than a decrease usually expected for weakening Kondo effect following lattice expansion. This unusual Kondo and magnetic ordering behavior of this solid solution possibly arises from disorder and/or structural features.

３成分系ＰｂＺｒＯ３‐ＰｂＴｉＯ３‐Ｐｂ（Ｍｎ１／３Ｓｂ２／３）Ｏ３圧電セラミックスの電気的及び機械的特性

The pseudo-ternary solid solution system PbZrO3-PbTiO3-Pb(Mn1/3Sb2/3)O3(PZ-PT-PMS) piezoelectric ceramics were synthesized. However, the value of tolerance factor with Pb(Mn1/3Sb2/3)O3 was nearly 1, Pb(Mn1/3Sb2/3)O3 does not exist itself as a single phase perovskite structure. Pb2Sb2O7 and Pb2MnO4 coexisted. But the small amount of PMS added PZ-PT-PMS showed a single phase perovskite structure. The piezoelectric properties were significantly changed near morphotropic phase boundary (MPB). Small amount of Mn2O3 addition to PZ-PT-PMS improved electromechanical coupling factor (kp) and mechanical quality factor (Qm). The four point bending strength of PZ-PT-PMS was 81.7MPa. And the value of Weibull modulus was 9.0.

Magnetic ordering and the Kondo effect in the alloys, Ce 2Co 1− xPd xSi 3

The compound Ce 2CoSi 3, crystallizing in a AlB 2-derived hexagonal structure, has been recently identified as a Kondo lattice with a non-magnetic ground state. Here, we report the influence of gradual replacement of Co by Pd on the magnetic behaviour in the pseudo-ternary solid solution, Ce 2Co 1− x Pd x Si 3, by magnetization (2–300 K), electrical resistivity (2–300 K) and heat-capacity (0.7–30 K) measurements to bring out a transformation from non-magnetic to magnetic ordering. Distinct features attributable to the existence of a competition between the Kondo effect and magnetic ordering with varying x and temperature are observed in the electrical resistivity data. The results reveal that small substitutions of Pd ( x=0.2–0.3) are sufficient to induce magnetic ordering of the Ce ions at low temperatures. The strength of the Kondo interaction as indicated by the paramagnetic Curie temperature decreases monotonically with increasing Pd content. A notable finding is that there are qualitative changes in the isothermal magnetization data in the magnetically ordered state, as if there are modifications in the magnetic structure with changes in the Co/Pd composition. The importance of electronic structure relative to unit-cell volume in deciding magnetic characteristics of this class of compounds is brought out taking into account the trends in the magnetic behaviour of isostructural Ce compounds.

Activities of Al in the Al-Ga-In-Sb system in the temperature range of 1073–1273k

The multicomponent alloy systems containing group III and V elements are particularly important for their electrical and optoelectronic applications. An accurate knowledge of their thermodynamic properties provides the essential tool in the determination of the phase equilibria which will be useful in processing the semiconducting materials. It may be mentioned that Zbitnew et al. [1] studied the quaternary system using x-ray Debye Scherrer powder photographic technique and x-ray fluorescence for the lattice parameter measurements and the chemical analysis respectively. They have shown that there is complete miscibility between Al-Sb, Ga-Sb, and InSb compounds which results in the formation of isomorphous pseudoternary solid solutions. Thermodynamic modelling of the quaternary system has been carried out by Sharma et al. [2] using a quasi sub-sub regular solution model based on the available information of the constituent binary and ternary properties. In the absence of any activity data, the present investigation measures the activities of Al in the liquid Al-Ga-In-Sb system using a concentration cell of the type.

Magnetic behavior of the alloys (Ce 1− xY x) 2PdSi 3

The results of X-ray diffraction (Cu K α), electrical resistivity (ρ), heat capacity ( C) and magnetic susceptibility (χ) measurements are reported for a new pseudoternary solid solution, (Ce 1− x Y x ) 2PdSi 3 ( x = 0.0, 0.2, 0.5, 0.8, 1.0). The X-ray diffraction patterns indicate that single phase alloys can be formed in a derived version of the AIB 2-type hexagonal structure for x ≥ 0.2, while for x = 0.0, apparently there is an additional weak phase. In the case of the alloy Ce 2PdSi 3, the majority of Ce ions do not exhibit magnetic ordering down to 1.4 K, though magnetic ordering at 7 K from one of the two crystallographically inequivalent sites cannot be ruled out. For other compositions, no magnetic ordering is observed above 1.4 K. The Kondo effect is operative in all these alloys, with the strength of the Kondo effect increasing with the compression of the lattice by the gradual replacement of Ce by Y. The C/ T exhibits a low temperature enhancement in all Ce containing alloys.

Stability of PbZrO 3-PbTiO 3-Pb(Mn 1/3Sb 2/3)O 3 Piezoelectric Ceramics under Vibration-Level Change

Vibration-level characteristics of electromechanical properties in the pseudo-ternary solid solution system PbZrO3-PbTiO3-Pb(Mn1/3Sb2/3)O3 ceramics were studied using a constant current control method. Stability under a vibration-level change was determined from the measurements of Young's modulus Y0 E and mechanical dissipation factor Q m-1. Durability degree for a high vibration-level excitation was estimated by a heat generation phenomenon. The durability was found to be dependent on the stability. As the stability increased, the durability also increased. The durability degree for a high vibration-level excitation was improved in the pseudo-ternary solid solution system PbZrO3-PbTiO3-Pb(Mn1/3Sb2/3)O3 ceramics over the binary solid solution system PbZrO3-PbTiO3 ceramics.

Electro-Mechanical Properties of PbZrO3-PbTiO3 -Pb(Mn1/3Sb2/3)O3 Ceramics Under Vibration-Level Change

AbstractElectro-mechanical properties in the pseudo-ternary solid solution system of PbZrO3-PbTiO3- Pb(Mn1/3Sb2/3)O3 piezoelectric ceramics were studied by changing the vibration- level using a constant current / velocity driving method. The vibration velocity is proportional to the driving electric field under a relatively low field. The velocity, however, deviates from a linear relationship as electric field increases and converges on a certain value.The increase of the vibration-level is accompanied by a large amount of heat generation as well, and this heat generation sets a practical upper limit of the vibration-level. The heat generation is caused by a dissipated-vibration-energy which is represented as a function of vibration velocity and the constants depending on the materials and transducers.In these pseudo-ternary solid solution ceramics, the compositional ratio which shows excellent electro-mechanical properties under a relatively low vibration-level does not necessarily coincide with the compositional ratio which is excellent under a relatively high vibration-level.

4f-electric quadrupolar anomalies in PrCu2Si2 and its pseudoternary solid solutions

Experimental observations for possible presence of 4f quadrupolar Kondo effect in PrCu2Si2 are critically discussed. A comparison of the low temperature properties of the alloys, PrxY1−xCu2Si2 (x=0.05, 0.2 and 0.4), seems to signal the existence of 4f electric quadrupolar glass phenomenon around 4K forx=0.2.

Competition between Kondo effect and magnetic ordering in CeOd 2Ge 2

The results of electrical resistivity (θ) measurements on the pseudoternary solid solutions, Ce 1-wY wPd 2Ge 2 and Ce 1-vLa vPd 2Ge 2, in the temperature interval 1.4–300K show that the substitution involving Y is less effective in depressing the Néel temperature of Ce sub-lattice than the La substitution in CePd 2Ge 2 (T N ⋍ 5.1K). This observation could be interpreted in terms of the existence of a competition between the two phenomena — magnetism and Kondo effect- in this system. We present evidence to show that the electronic structure changes following iso-valent ionic substitutions should not be ignored in any quantitative understanding of such competing phenomena.

Incoherent Kondo lattice behaviour in CeCu 3Ga 2

The results of magnetic susceptibility (4.2–300 K), electrical resistivity (1.5–300 K) and heat capacity (1.5–70 K) measurements are reported on the pseudoternary solid solution, Ce 1− x La x Cu 3Ga 2. The data prove that the observed properties of CeCu 3Ga 2 are single ionic in nature and support our claim that this compound is an incoherent Kondo lattice.

Heat-capacity behavior of the alloys Pr 1− xGd xCu 2Si 2

The results of heat capacity measurements (0.3–40 K) on the pseudoternary solid solution Pr 1− x Gd x Cu 2Si 2 (0 < × ≤ 1) are reported. The data show interesting features attributable to magnetic-ordering and spin-reorientation effects. The x dependence of the data indicates heavy-fermion-like behaviour for PrCu 2Si 2.

Observation of heavy-fermion like behaviour and anomalous magnetism in a Pr-based metal

The results of magnetic susceptibility, electrical resistivity and heat capacity measurements on the pseudoternary solid solutions, Pr 1−xGd xCu 2Si 2, are reported. These is an unusual enhancement of Néel temperature (T N) of Pr sub-lattice in PrCu 2Si 2 (T N = 21K) over that of GdCu 2Si 2 (T N = 13K). Present results indicate that this anomalous magnetism gets relatively depressed by positive chemical pressure effects induced by Gd or Y substitution. Interestingly, the linear coefficient of heat capacity above T N is found to be large for PrCu 2 Si 2 (∾225 mJ/mol K 2) and this parameter undergoes a drastic reduction with Gd substitution. Such a strong dependence of this linear term on the positive chemical pressure indicates possible heavy fermion behaviour of Pr in a metallic environment.

Synthesis and characterization of the Zn xCd 1− xIn 2S 4 pseudoternary solid solution

We have synthesized several compounds of the Zn x Cd 1− x In 2S 4 family by solid phase reactions and chemical transport reactions using iodine. The reaction products have been characterized as to composition, structure, and lattice dynamics. Here we discuss and compare the different results obtained by the two synthesis methods.

Crystalline and magnetic structures in REAlxGa2 − x systems [formula omitted]: Part I: Crystalline structures

Part I describes results of crystalline structures found for the NdAl x Ga 2 − x and ErAl x Ga 2 − x pseudoternary solid solution systems (0 ⪕ x ⪕ 2). Characterization techniques include X-ray diffraction, electron microprobe analysis and DTA measurements.

Crystalline and magnetic structures in REAlxGa2 − x systems [formula omitted]: Part II: Magnetic structures

Part II describes results on bulk magnetic properties, transition temperatures, magnetic structures and magnetic moments found for the NdAl x Ga 2 − x and ErAl x Ga 2 − x pseudoternary solid solution systems (0 ⪕ x ⪕ 2). Characterization techniques include electron microprobe analysis, induction magnetometer, X-ray and neutron diffraction. We found ferromagnetic as well as antiferromagnetic order with parallel and incommensurate spiral structures. These spiral structures are of cycloidal or triangular screw axis type.