Abstract
The magnetic order and the spin dynamics in the antiferromagnetic entropy-stabilized oxide (Mg0.2Co0.2Ni0.2Cu0.2Zn0.2)O (MgO-ESO) have been studied using muon spin relaxation (μSR) and inelastic neutron scattering. We find that antiferromagnetic order develops gradually in the sample volume as it is cooled below 140 K, becoming fully ordered around 100 K. The spin dynamics show a critical slowing down in the vicinity of the transition, and the magnetic order parameter grows continuously in the ordered state. These results indicate that the antiferromagnetic transition is continuous but proceeds with a Gaussian distribution of ordering temperatures. The magnetic contribution to the specific heat determined from inelastic neutron scattering likewise shows a broad feature centered around 120 K. High-resolution inelastic neutron scattering further reveals an initially gapped spectrum at low temperature which sees an increase in a quasielastic contribution upon heating until the ordering temperature.
| Original language | English |
|---|---|
| Article number | 074405 |
| Journal | Physical Review Materials |
| Volume | 4 |
| Issue number | 7 |
| DOIs | |
| State | Published - Jul 2020 |
Funding
We thank Gerald Morris, Bassam Hitti, and Donald Arseneau for their support at the beamline at TRIUMF, John Budai and Doug Abernathy for their help at the ARCS beamline, and Melissa Graves-Brook for her help at the HYSPEC beamline. The work at Brigham Young University (BYU) was made possible by funds provided by the College of Physical and Mathematical Sciences at BYU. Material synthesis, inelastic neutron scattering and muon spin resonance work by R.P.H. (INS, μSR), M.E.M. (INS) and J.J.Z. (INS, synthesis), and J.Y. (synthesis) was supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division and work by B.W. (INS) was supported by the United States Department of Energy, Office of Science, Office of Basic Energy Sciences, Scientific User Facilities Division, both under Contract Number DE-AC05-00OR22725. This study used in parts resources at the Spallation Neutron Source (SNS), a DOE Office of Science User Facility operated by the Oak Ridge National Laboratory (INS measurements performed at the ARCS and HYSPEC beamlines).