Magnetism and negative magnetoresistance of two magnetically ordering, rare-earth-containing zintl phases with a new structure type: EuGa 2Pn2 (Pn=P, As)

Andrea M. Goforth, Håkon Hope, Cathie L. Condron, Susan M. Kauzlarich, Newell Jensen, Peter Klavins, Samuel MaQuilon, Zachary Fisk

Research output: Contribution to journalArticle

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Abstract

Single crystals of EuGa2Pn2 (Pn=P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a=9.2822(9) A, =3.8967(4) A, c=12.0777(11) A, Β=95.5220(10), R1= 0.0148, wR2=0.0325 (EuGa2P2) and a=9.4953(7) A, b=4.0294(3) A, c=12.4237(9) A, Β =95.3040(10), R1=0.0155, wR2=0.0315 (EuGa2As2)). The structures consist of alternating layers of two-dimensional Ga2Pn2 anions and Eu cations. The anion layers are composed of Ga2Pn6 staggered, ethane-like moieties having a rare Ga-Ga bonding motif; these moieties are connected in a complex fashion bymeans of shared Pn atoms. Both structures showsmall residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (< 2%) wheremost of the atoms are the same, but there is a difference in bonding that leads to one-dimensional ribbons of parallel Ga2Pn6 staggered, ethane-like moieties. The compounds can be understood within the Zintl formalism, but show metallic resistivity. Magnetization measurements performed on single crystals show low-temperature magnetic anisotropy as well as multiple magnetic ordering events that occur at and below 24 and 20 K for the phosphorus and arsenic analogs, respectively. The magnetic coupling between Eu ions is attributed to indirect exchange via an RKKY interaction, which is consistent with the metallic behavior. The compounds display large negative magnetoresistance of up to-80 and-30%(MR=[(F(H)-F(0))/F(H)] 100%) for Pn=P,As, respectively,which is maximal at the magnetic ordering temperatures in the highest measured field (5T).

Original languageEnglish (US)
Pages (from-to)4480-4489
Number of pages10
JournalChemistry of Materials
Volume21
Issue number19
DOIs
StatePublished - Oct 13 2009
Externally publishedYes

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Magnetism
Magnetoresistance
Rare earths
Magnetization
Atoms
Ethane
Single crystals
Anions
Negative ions
Magnetic couplings
Magnetic anisotropy
Arsenic
Phosphorus
Carrier concentration
Cations
Molten materials
Ion exchange
Positive ions
Ions
Fluxes

ASJC Scopus subject areas

  • Materials Chemistry
  • Chemical Engineering(all)
  • Chemistry(all)

Cite this

Magnetism and negative magnetoresistance of two magnetically ordering, rare-earth-containing zintl phases with a new structure type : EuGa 2Pn2 (Pn=P, As). / Goforth, Andrea M.; Hope, Håkon; Condron, Cathie L.; Kauzlarich, Susan M.; Jensen, Newell; Klavins, Peter; MaQuilon, Samuel; Fisk, Zachary.

In: Chemistry of Materials, Vol. 21, No. 19, 13.10.2009, p. 4480-4489.

Research output: Contribution to journalArticle

Goforth, AM, Hope, H, Condron, CL, Kauzlarich, SM, Jensen, N, Klavins, P, MaQuilon, S & Fisk, Z 2009, 'Magnetism and negative magnetoresistance of two magnetically ordering, rare-earth-containing zintl phases with a new structure type: EuGa 2Pn2 (Pn=P, As)', Chemistry of Materials, vol. 21, no. 19, pp. 4480-4489. https://doi.org/10.1021/cm901219u
Goforth, Andrea M. ; Hope, Håkon ; Condron, Cathie L. ; Kauzlarich, Susan M. ; Jensen, Newell ; Klavins, Peter ; MaQuilon, Samuel ; Fisk, Zachary. / Magnetism and negative magnetoresistance of two magnetically ordering, rare-earth-containing zintl phases with a new structure type : EuGa 2Pn2 (Pn=P, As). In: Chemistry of Materials. 2009 ; Vol. 21, No. 19. pp. 4480-4489.
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title = "Magnetism and negative magnetoresistance of two magnetically ordering, rare-earth-containing zintl phases with a new structure type: EuGa 2Pn2 (Pn=P, As)",
abstract = "Single crystals of EuGa2Pn2 (Pn=P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a=9.2822(9) A, =3.8967(4) A, c=12.0777(11) A, Β=95.5220(10), R1= 0.0148, wR2=0.0325 (EuGa2P2) and a=9.4953(7) A, b=4.0294(3) A, c=12.4237(9) A, Β =95.3040(10), R1=0.0155, wR2=0.0315 (EuGa2As2)). The structures consist of alternating layers of two-dimensional Ga2Pn2 anions and Eu cations. The anion layers are composed of Ga2Pn6 staggered, ethane-like moieties having a rare Ga-Ga bonding motif; these moieties are connected in a complex fashion bymeans of shared Pn atoms. Both structures showsmall residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (< 2{\%}) wheremost of the atoms are the same, but there is a difference in bonding that leads to one-dimensional ribbons of parallel Ga2Pn6 staggered, ethane-like moieties. The compounds can be understood within the Zintl formalism, but show metallic resistivity. Magnetization measurements performed on single crystals show low-temperature magnetic anisotropy as well as multiple magnetic ordering events that occur at and below 24 and 20 K for the phosphorus and arsenic analogs, respectively. The magnetic coupling between Eu ions is attributed to indirect exchange via an RKKY interaction, which is consistent with the metallic behavior. The compounds display large negative magnetoresistance of up to-80 and-30{\%}(MR=[(F(H)-F(0))/F(H)] 100{\%}) for Pn=P,As, respectively,which is maximal at the magnetic ordering temperatures in the highest measured field (5T).",
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AU - Goforth, Andrea M.

AU - Hope, Håkon

AU - Condron, Cathie L.

AU - Kauzlarich, Susan M.

AU - Jensen, Newell

AU - Klavins, Peter

AU - MaQuilon, Samuel

AU - Fisk, Zachary

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N2 - Single crystals of EuGa2Pn2 (Pn=P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a=9.2822(9) A, =3.8967(4) A, c=12.0777(11) A, Β=95.5220(10), R1= 0.0148, wR2=0.0325 (EuGa2P2) and a=9.4953(7) A, b=4.0294(3) A, c=12.4237(9) A, Β =95.3040(10), R1=0.0155, wR2=0.0315 (EuGa2As2)). The structures consist of alternating layers of two-dimensional Ga2Pn2 anions and Eu cations. The anion layers are composed of Ga2Pn6 staggered, ethane-like moieties having a rare Ga-Ga bonding motif; these moieties are connected in a complex fashion bymeans of shared Pn atoms. Both structures showsmall residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (< 2%) wheremost of the atoms are the same, but there is a difference in bonding that leads to one-dimensional ribbons of parallel Ga2Pn6 staggered, ethane-like moieties. The compounds can be understood within the Zintl formalism, but show metallic resistivity. Magnetization measurements performed on single crystals show low-temperature magnetic anisotropy as well as multiple magnetic ordering events that occur at and below 24 and 20 K for the phosphorus and arsenic analogs, respectively. The magnetic coupling between Eu ions is attributed to indirect exchange via an RKKY interaction, which is consistent with the metallic behavior. The compounds display large negative magnetoresistance of up to-80 and-30%(MR=[(F(H)-F(0))/F(H)] 100%) for Pn=P,As, respectively,which is maximal at the magnetic ordering temperatures in the highest measured field (5T).

AB - Single crystals of EuGa2Pn2 (Pn=P, As) were grown from a molten Ga flux and characterized by single-crystal X-ray diffraction at 100(1) K. They are isostructural and crystallize in a new structure type (monoclinic, P2/m, a=9.2822(9) A, =3.8967(4) A, c=12.0777(11) A, Β=95.5220(10), R1= 0.0148, wR2=0.0325 (EuGa2P2) and a=9.4953(7) A, b=4.0294(3) A, c=12.4237(9) A, Β =95.3040(10), R1=0.0155, wR2=0.0315 (EuGa2As2)). The structures consist of alternating layers of two-dimensional Ga2Pn2 anions and Eu cations. The anion layers are composed of Ga2Pn6 staggered, ethane-like moieties having a rare Ga-Ga bonding motif; these moieties are connected in a complex fashion bymeans of shared Pn atoms. Both structures showsmall residual electron densities that can be modeled by adding a Eu atom and removing two bonded Ga atoms, resulting in structures (< 2%) wheremost of the atoms are the same, but there is a difference in bonding that leads to one-dimensional ribbons of parallel Ga2Pn6 staggered, ethane-like moieties. The compounds can be understood within the Zintl formalism, but show metallic resistivity. Magnetization measurements performed on single crystals show low-temperature magnetic anisotropy as well as multiple magnetic ordering events that occur at and below 24 and 20 K for the phosphorus and arsenic analogs, respectively. The magnetic coupling between Eu ions is attributed to indirect exchange via an RKKY interaction, which is consistent with the metallic behavior. The compounds display large negative magnetoresistance of up to-80 and-30%(MR=[(F(H)-F(0))/F(H)] 100%) for Pn=P,As, respectively,which is maximal at the magnetic ordering temperatures in the highest measured field (5T).

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