- The isothermal section of the Er-Fe-Sb ternary system at 773 K
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The phase relation of the Er-Fe-Sb ternary system at 773 K has been investigated mainly by means of X-ray powder diffraction with the aid of optical microscopy and differential thermal analysis. This section consists of 12 single-phase regions, 22 two-phase regions and 11 three-phase regions. A ternary compound Er6FeSb2 has been confirmed.
- Cai, Gemei,Wei, Xiangzhong,Zeng, Lingmin
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- Synthesis and Transport Properties of the Family of Zintl Phases Ca3RESb3(RE = La-Nd, Sm, Gd-Tm, Lu): Exploring the Roles of Crystallographic Disorder and Core 4f Electrons for Enhancing Thermoelectric Performance
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Zintl phases with complex crystal structures have been studied as promising candidate materials for thermoelectric (TE) applications. Here, we report the syntheses of the family of rare-earth metal Zintl phases with the general formula Ca4-xRExSb3 (x ≈ 1; RE = La-Nd, Sm, Gd-Tm, Lu). The structural elucidation is based on refinements of single-crystal X-ray diffraction data for 12 unique chemical compositions. The cubic structure is confirmed as belonging to the anti-Th3P4 structure type (space group I4ˉ 3d, no. 220, Z = 4), where the Ca and RE atoms share the same atomic site with ca. 75 and 25% occupancies, respectively. Such crystallographic disordering of divalent Ca and trivalent RE atoms in the structure provides a pathway to intricate bonding. The latter, together with the presence of heavy elements such as Sb and the lanthanides, are expected to enhance the scattering probability of phonons, thereby leading to low thermal conductivity κ comparable to that of the ordered RE4Sb3. The drive of the hypothetical parent compound Ca4Sb3 to be stabilized by alloying with rare-earth metals can be understood following the Zintl-Klemm concept, as the resultant formula may be rationalized as (Ca2+)3RE3+(Sb3-)3, indicating the realization of closed-shell electronic configurations for all elements. This notion is confirmed by electronic structure calculations, which reveal narrow bandgaps Eg = 0.77 and 0.53 eV for Ca3LaSb3 and Ca3LuSb3, respectively. In addition, the incorporation of RE atoms into the structure drives the phase into a state of a degenerate semiconductor with dominant hole charge carriers.
- Ogunbunmi, Michael O.,Baranets, Sviatoslav,Bobev, Svilen
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p. 9382 - 9392
(2021/12/13)
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- Synthesis, structure, magnetic and transport properties of LnFeSb 3 (Ln = Pr, Nd, Sm, Gd, and Tb) - Tuning of anisotropic long-range magnetic order as a function of Ln
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Single crystals of LnFeSb3 (Ln = Pr, Nd, Sm, Gd, and Tb) have been grown from excess Sb flux. The crystal structure consists of ∞2[FeSb2] octahedra separated by layers of Ln atoms and nearly square planar nets of ∞ 2[Sb2]. These compounds are metallic and display anisotropic magnetic properties. Long-range antiferromagnetic order is observed in the Sm, Gd, and Tb samples when the magnetic field is applied along the crystallographic a-axis. Evidence of magnetic ordering in all the samples is observed for the field applied parallel to the layers. The magnetic properties are well-described by considering only the magnetic interactions between the Ln 4f moments, with no contribution from the Fe sublattice. Herein, we report the crystal growth, structure, magnetization, transport, and chemical stabilities of the title compounds. The Royal Society of Chemistry.
- Phelan, W. Adam,Nguyen, Giang V.,Karki, Amar B.,Young, David P.,Chan, Julia Y.
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p. 6403 - 6409
(2010/09/06)
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- Pressure-induced phase transitions in lanthanide monoantimonides with a NaCl-type structure
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By use of synchrotron radiation the powder x-ray diffraction of LnSb (Ln=lanthanide) with a NaCl-type structure has systematically been studied up to 40 GPa at room temperature. First-order phase transitions with the crystallographic change occur for LnSb at high pressures. The structure of the high-pressure phases of LnSb is classified into three groups. The lighter LnSb (Ln=La, Ce, Pr, and Nd) have the tetragonal structure (distorted CsCl-type) at high pressures. The high-pressure form of the middle LnSb (Ln=Sm, Gd, and Tb) is unknown. The heavier LnSb (Ln=Dy, Ho, Er, Tm, and Lu) show the typical NaCl-CsCl (B1-B2) transition at high pressures though the same transition is not observed in the heavier LnP and LnAs. The transition pressures of LnSb increase with decreasing lattice constant in the NaCl-type structure and do not depend on the structure of their high-pressure phases. The high-pressure structural behavior of LnSb is discussed.
- Shirotani, Ichimin,Hayashi, Junichi,Yamanashi, Keigo,Ishimatsu, Naoki,Shimomura, Osamu,Kikegawa, Takumi
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- 121Sb MOESSBAUER INVESTIGATION OF THE RARE EARTH ANTIMONIDES.
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**1**2**1Sb Moessbauer spectra have been obtained for the series R Sb (R equals La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, and Yb) at 78 K and for a selection of the compounds at 5. 5 K. At 78 K all the spectra show a single line. The isomer shifts are close to that of InSb and show a linear increase with increasing atomic number of the rare earth ion. Many of the rare earth antimonides exhibit a variety of magnetic and structural phase transitions at a sufficiently low temperature. Spectra obtained at 5. 5 K are interpreted in terms of these phase transitions.
- Holbourn,Woodhams
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p. 186 - 194
(2008/10/09)
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