title: Synthesis, Structure, and Complex Magnetism of MIr2In8 (M = Eu, Sr).
abstract: We report the synthesis, crystal structure, and physical properties of two new polar intermetallic compounds, EuIr2In8 and SrIr2In8. Both were synthesized in good yield using In metal as a reactive flux medium, enabling the growth of large crystals for physical property measurements. They crystallize in the orthorhombic space group Pbam with the CeFe2Al8 structure type, which is sometimes also referred to as the CaCo2Al8 structure type. The two analogues have unit cell parameters of a = 13.847(3) Å, b = 16.118(3) Å, and c = 4.3885(9) Å for M = Eu and a = 13.847(3) Å, b = 16.113(3) Å, and c = 4.3962(9) Å for M = Sr at room temperature. SrIr2In8 is a diamagnetic metal with no local magnetic moments on either the Sr or Ir sites, and the diamagnetic contribution from core electrons overwhelms the expected Pauli paramagnetism normally seen in intermetallic compounds. Magnetism in EuIr2In8 is dominated by the local Eu moments, which order antiferromagnetically at 5 K in low applied fields. Increasing the field strength depresses the magnetic ordering temperature and also induces a spin reorientation at lower temperature, indicating complex competing magnetic interactions. Low-temperature heat capacity measurements show a significant enhancement of the Sommerfeld coefficient in EuIr2In8 relative to that in SrIr2In8, with estimated values of γ = 118(3) and 18.0(2) mJ mol(-1) K(-2), respectively.
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Calta
authors.affiliation: Department of Physics & Astronomy, Iowa State University , 12 Physics Hall, Ames, Iowa 50011, United States.|Division of Materials Science & Engineering, Ames Laboratory , Ames, Iowa 50011, United States.
authors.forename: Sergey L
authors.initials: SL
authors.lastname: Bud'ko
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.
authors.forename: Alexandra P
authors.initials: AP
authors.lastname: Rodriguez
authors.affiliation: Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Fei
authors.initials: F
authors.lastname: Han
authors.affiliation: Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Duck Young
authors.initials: DY
authors.lastname: Chung
authors.affiliation: Department of Chemistry, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208, United States.|Materials Science Division, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
authors.forename: Mercouri G
authors.initials: MG
authors.lastname: Kanatzidis