Abstract
In search of a quantum phase transition between the two-dimensional (2D) ferromagnetism of CaCo2-yAs2 and stripe-type antiferromagnetism in SrCo2As2, we instead find evidence for 1D magnetic frustration between magnetic square Co layers. We present neutron-diffraction data for Ca1-xSrxCo2-yAs2 that reveal a sequence of x-dependent magnetic transitions which involve different stacking of 2D ferromagnetically aligned layers with different magnetic anisotropy. We explain the x-dependent changes to the magnetic order by utilizing classical analytical calculations of a 1D Heisenberg model where single-ion magnetic anisotropy and frustration of antiferromagnetic nearest- and next-nearest-layer exchange interactions are all composition dependent.
| Original language | English |
|---|---|
| Article number | 024415 |
| Journal | Physical Review B |
| Volume | 100 |
| Issue number | 2 |
| DOIs | |
| State | Published - Jul 15 2019 |
Funding
We are grateful for assistance from D. Robinson with performing the x-ray experiments, and helpful conversations with T. W. Heitmann, D. H. Ryan, L. Ke, and D. Vaknin. Work at the Ames Laboratory was supported by the U.S. Department of Energy (DOE), Basic Energy Sciences, Division of Materials Sciences and Engineering, under Contract No. DE-AC02-07 CH11358. A portion of this research used resources at the High Flux Isotope Reactor, a U.S. DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. This research used resources of the Advanced Photon Source, a U.S. DOE Office of Science User Facility operated for the U.S. DOE Office of Science by Argonne National Laboratory under Contract No. DE-AC2-06 CH11357. Y.S. and P.P.O. acknowledge support from Iowa State University Startup Funds.