Abstract
Here, we present a study of the influence of microstructure on the magnetic properties of polycrystalline samples of the La1.5Sr0.5CoMnO6 double perovskite, with primary attention to the spontaneous exchange bias effect, a fascinating recently discovered phenomena for which some materials exhibit unidirectional magnetic anisotropy after being cooled in zero magnetic fields. By sintering La1.5Sr0.5CoMnO6 at different temperatures, we obtained samples with distinct average grain sizes, ranging from 1.54-6.65 μm. A detailed investigation of the material's structural, morphologic, electronic, and magnetic properties using x-ray powder diffraction, powder neutron diffraction, x-ray absorption near edge structure spectroscopy, scanning electron microscopy, and ac and dc magnetometry has revealed a systematic enhancement of the exchange bias effect with increasing the average grain size. This evolution is discussed in terms of changes in the material's porosity and grain morphology and its influence on the exchange couplings at the magnetic interfaces.
| Original language | English |
|---|---|
| Article number | 044408 |
| Journal | Physical Review Materials |
| Volume | 8 |
| Issue number | 4 |
| DOIs | |
| State | Published - Apr 2024 |
Funding
This work was supported by the Brazilian funding agencies: Fundacao Carlos Chagas Filho de Amparo Pesquisa do Estado do Rio de Janeiro (FAPERJ) [No. E-26/202.798/2019 and No. E-26/211.291/2021], Fundacao de Amparo Pesquisa do Estado de Goies (FAPEG) and Conselho Nacional de Desenvlovimento Cientifico e Tecnolegico (CNPq). This research used facilities of the Brazilian Synchrotron Light Laboratory (LNLS), part of the Brazilian Center for Research in Energy and Materials (CNPEM), a private nonprofit organization under the supervision of the Brazilian Ministry for Science, Technology, and Innovations (MCTI). The EMA beamline staff is acknowledged for their assistance during the experiments 20220583. Certain commercial equipment, instruments, or materials are identified in this document. Such identification does not imply recommendation or endorsement by the National Institute of Standards and Technology, nor does it imply that the products identified are necessarily the best available for the purpose. The views expressed in the paper do not necessarily represent the views of the DOE or the U.S. Government. The U.S. Government retains, and the publisher, by accepting the paper for publication, acknowledges that the U.S. Government retains a nonexclusive, paid-up, irrevocable, worldwide license to publish or reproduce the published form of this work or allow others to do so for U.S. Government purposes. A portion of this research used resources at the Spallation Neutron Source, a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory. A portion of this work was supported by NIST. R.A.K. gratefully acknowledges from the U.S. DOE Office of Energy Efficiency and Renewable Energy (EERE), Hydrogen and Fuel Cell Technologies Office (HFTO) Contract No. DE-ac36-8GO28308 to the National Renewable Energy Laboratory (NREL).