Abstract
The structure, magnetic properties, and 151Eu and 119Sn Mössbauer spectra of the solid-solution Eu11-xSrxZn4Sn2As12 are presented. A new commensurately modulated structure is described for Eu11Zn4Sn2As12 (R3m space group, average structure) that closely resembles the original structural description in the monoclinic C2/c space group with layers of Eu, puckered hexagonal Zn2As3 sheets, and Zn2As6 ethane-like isolated pillars. The solid-solution Eu11-xSrxZn4Sn2As12 (0 < x < 10) is found to crystallize in the commensurately modulated R3 space group, related to the parent phase but lacking the mirror symmetry. Eu11Zn4Sn2As12 orders with a saturation plateau at 1 T for 7 of the 11 Eu2+ cations ferromagnetically coupled (5 K) and shows colossal magnetoresistance at 15 K. The magnetic properties of Eu11Zn4Sn2As12 are investigated at higher fields, and the ferromagnetic saturation of all 11 Eu2+ cations occurs at ∼8 T. The temperature-dependent magnetic properties of the solid solution were investigated, and a nontrivial structure-magnetization correlation is revealed. The temperature-dependent 151Eu and 119Sn Mössbauer spectra confirm that the europium atoms in the structure are all Eu2+ and that the tin is consistent with an oxidation state of less than four in the intermetallic region. The spectral areas of both Eu(II) and Sn increase at the magnetic transition, indicating a magnetoelastic effect upon magnetic ordering.
| Original language | English |
|---|---|
| Pages (from-to) | 5711-5723 |
| Number of pages | 13 |
| Journal | Inorganic Chemistry |
| Volume | 60 |
| Issue number | 8 |
| DOIs | |
| State | Published - Apr 19 2021 |
Funding
The authors thank Nick Botto for assistance with microprobe analysis, Vaclav Petricek, Michael Dusek, and Oliver Janka for discussions about modulated structures, and Michael Ruf for his help with determining the modulation in one of the compounds using the Bruker APEX3 software. This work was supported by National Science Foundation (NSF) Grants DMR-1709382 and DMR-201156-0. A.K.H. acknowledges a UC Davis Dean’s Distinguished Graduate Fellowship. A portion of this work was performed at the National High Magnetic Field Laboratory, which is supported by NSF Cooperative Agreement DMR-1644779 and the state of Florida. The Mössbauer spectral work at Oak Ridge National Laboratory (J.Z. and R.P.H.) was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division.