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Title: Unusual Phase Diagram of CeOs 4Sb 12

Abstract

Filled skutterudite compounds, with the formula MT 4X 12, where M is an alkali metal, alkaline-earth, lanthanide, or actinide, T is Fe, Ru, or Os, and X is P, As, or Sb, display a wide variety of interesting phenomena caused by strong electron correlations [1]. Among these, the three compounds CeOs 4Sb 12, PrOs 4Sb 12, and NdOs 4Sb 12, formed by employing Periodic Table neighbors for M, span the range from an antiferromagnetic (AFM) semimetal (M = Ce) via a 1.85 K unconventional (quadrupolar-fluctuation mediated) superconductor (M = Pr) to a 1 K ferromagnet (FM; M = Nd). In the course of an extended study of these compounds, we uncovered an unusual phase diagram for CeOs 4Sb 12.

Authors:
 [1];  [2];  [3];  [4]
  1. Fresno State Univ., Fresno, CA (United States)
  2. Warwick Univ., Coventry (United Kingdom)
  3. Univ. of California, San Diego, CA (United States)
  4. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1345909
Report Number(s):
LA-UR-17-21725
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; High Magnetic Field Science

Citation Formats

Ho, P. -C., Goddard, P. A., Maple, M. B., and Singleton, John. Unusual Phase Diagram of CeOs4Sb12. United States: N. p., 2017. Web. doi:10.2172/1345909.
Ho, P. -C., Goddard, P. A., Maple, M. B., & Singleton, John. Unusual Phase Diagram of CeOs4Sb12. United States. doi:10.2172/1345909.
Ho, P. -C., Goddard, P. A., Maple, M. B., and Singleton, John. Wed . "Unusual Phase Diagram of CeOs4Sb12". United States. doi:10.2172/1345909. https://www.osti.gov/servlets/purl/1345909.
@article{osti_1345909,
title = {Unusual Phase Diagram of CeOs4Sb12},
author = {Ho, P. -C. and Goddard, P. A. and Maple, M. B. and Singleton, John},
abstractNote = {Filled skutterudite compounds, with the formula MT4X12, where M is an alkali metal, alkaline-earth, lanthanide, or actinide, T is Fe, Ru, or Os, and X is P, As, or Sb, display a wide variety of interesting phenomena caused by strong electron correlations [1]. Among these, the three compounds CeOs4Sb12, PrOs4Sb12, and NdOs4Sb12, formed by employing Periodic Table neighbors for M, span the range from an antiferromagnetic (AFM) semimetal (M = Ce) via a 1.85 K unconventional (quadrupolar-fluctuation mediated) superconductor (M = Pr) to a 1 K ferromagnet (FM; M = Nd). In the course of an extended study of these compounds, we uncovered an unusual phase diagram for CeOs4Sb12.},
doi = {10.2172/1345909},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Mar 01 00:00:00 EST 2017},
month = {Wed Mar 01 00:00:00 EST 2017}
}

Technical Report:

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  • We use MHz conductivity, torque magnetometer, and magnetization measurements to report on single crystals of CeOs 4 Sb 12 and NdOs 4 Sb 12 using temperatures down to 0.5 K and magnetic fields of up to 60 tesla. The field-orientation dependence of the de Haas-van Alphen and Shubnikov-de Haas oscillations is deduced by rotating the samples about the [ 010 ] and [ 0more » $$\bar{1}$$ 1 1 ] directions. Our results indicate that NdOs 4 Sb 12 has a similar Fermi surface topology to that of the unusual superconductor PrOs 4 Sb 12 , but with significantly smaller effective masses, supporting the importance of local phonon modes in contributing to the low-temperature heat capacity of NdOs 4 Sb 12 . By contrast, CeOs 4 Sb 12 undergoes a field-induced transition from an unusual semimetal into a high-field, high-temperature state characterized by a single, almost spherical Fermi-surface section. Furthermore, the behavior of the phase boundary and comparisons with models of the band structure lead us to propose that the field-induced phase transition in CeOs 4 Sb 12 is similar in origin to the well-known α - γ transition in Ce and its alloys.« less
  • Spin and polarization flop transitions are fascinating, especially when controlled by external stimuli like magnetic and electric field and accompanied by large material responses involving multiple degrees of freedom. Multiferroics like MnWO 4, TbMnO 3, and Ni 3TeO 6 are flagship examples and owe their remarkable properties, for instance field control of polarization and polarization flops combined with spin helix reorientation, to the anisotropy and heavy centers that bring in spin-orbit coupling. The family of A 2FeX 5.H 2O erythrosiderites (A = K, Rb, NH 4; B = Fe, Mn, Co; X = Cl, Br, H 2O) drew our attentionmore » due to the rich chemical tuning possibilities, complex phase diagrams, and topological similarities to oxide multiferroics.1 (NH 4) 2FeCl 5.H 2O is the flagship example (Fig. 1(a)). It displays a high temperature order-disorder transition involving long-range hydrogen bonding of the NH 4 + group and two successive low temperature magnetic transitions below which non-collinear magnetic order and ferroelectricity are established.1 In addition to the magnetically-induced electric polarization that arises below 6.9 K (P = 3 μC/m 2 along a and a smaller component along b), applied field reveals a peculiar hysteretic spin flop transition near 4.5 T above which polarization flops from the a- to the c-axis. There are elastic components as well. Taken together, these findings raise questions about the interactions that induce this behavior and whether additional non-equilibrium phases might be accessed under even higher magnetic fields.« less
  • Investigations on phase relationships and crystal structures have been conducted on several ternary rare-earth titanium antimonide systems. The isothermal cross-sections of the ternary RE-Ti-Sb systems containing a representative early (RE=La) and late rare-earth element (RE=Er) have been constructed at 800 deg. C. In the La-Ti-Sb system, the previously known compound La{sub 3}TiSb{sub 5} was confirmed and the new compound La{sub 2}Ti{sub 7}Sb{sub 12} (own type, Cmmm, Z=2, a=10.5446(10) A, b=20.768(2) A, and c=4.4344(4) A) was discovered. In the Er-Ti-Sb system, no ternary compounds were found. The structure of La{sub 2}Ti{sub 7}Sb{sub 12} consists of a complex arrangement of TiSb{sub 6}more » octahedra and disordered fragments of homoatomic Sb assemblies, generating a three-dimensional framework in which La atoms reside. Other early rare-earth elements (RE=Ce, Pr, Nd) can be substituted in this structure type. Attempts to prepare crystals in these systems through use of a tin flux resulted in the discovery of a new Sn-containing pseudoternary phase RETi{sub 3}(Sn{sub x}Sb{sub 1-x}){sub 4} for RE=Nd, Sm (own type, Fmmm, Z=8; a=5.7806(4) A, b=10.0846(7) A, and c=24.2260(16) A for NdTi{sub 3}(Sn{sub 0.1}Sb{sub 0.9}){sub 4}; a=5.7590(4) A, b=10.0686(6) A, and c=24.1167(14) A for SmTi{sub 3}(Sn{sub 0.1}Sb{sub 0.9}){sub 4}). Its structure consists of double-layer slabs of Ti-centred octahedra stacked alternately with nets of the RE atoms; the Ti atoms are arranged in kagome nets. - Graphical abstract: La{sub 2}Ti{sub 7}Sb{sub 12} contains sectioned layers consisting of Ti-centred octahedra linked by corner- and face-sharing.« less
  • The crystal structures of LaRu{sub 4}P{sub 12} and CeRu{sub 4}P{sub 12} are refined by the Rietveld analysis of the powder X-ray diffraction data. The bond distances and bond angles in both phosphides are obtained. La{sub 1{minus}x}Ce{sub x}Ru{sub 4}P{sub 12} (x = 0, 01, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.75, 0.8, 0.9, and 1) and CeOs{sub 4}P{sub 12} are prepared at high temperatures and high pressures. Powder X-ray diffractions of the alloys are studied at room temperature. The lattice parameters of the alloys do not change linearly with increasing x and markedly deviate from linear between x < 0.4 andmore » x = 0.6. The formal oxidation number of Ce atoms in the alloys is +3 below x = 0.6. The electrical and magnetic properties of the alloys CeRu{sub 4}P{sub 12} and CeOs{sub 4}P{sub 12} are studied at low temperatures. The metal-to-insulator transition and magnetic ordering appear at around x = 0.6. Above x = 0.7 the alloys behave as a semiconductor. CeOs{sub 4}P{sub 12} exhibits a semiconducting behavior, with an activation energy of 0.034 eV. CeRu{sub 4}P{sub 12} and CeOs{sub 4}P{sub 12} show a very small, nearly temperature-independent susceptibility. Electrical and magnetic properties of the alloys, CeRu{sub 4}P{sub 12} and CeOs{sub 4}P{sub 12} are discussed.« less