The magnetic order and the spin dynamics in the antiferromagnetic entropy-stabilized oxide (Mg${}_{0.2}$Co${}_{0.2}$Ni${}_{0.2}$Cu${}_{0.2}$Zn${}_{0.2}$)O (MgO-ESO) have been studied using muon spin relaxation () 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.

中文翻译：

---

熵稳定的氧化物反铁磁体中的自旋动力学和几乎连续的磁性相变

反铁磁熵稳定氧化物（Mg）的磁序和自旋动力学${}_{0.2}$有限公司${}_{0.2}$你${}_{0.2}$铜${}_{0.2}$锌${}_{0.2}$）O（MgO-ESO）已使用μ子自旋弛豫（）和非弹性中子散射进行了研究。我们发现，当样品体积冷却至140 K以下时，反铁磁序会逐渐发展，在100 K附近变得完全有序。自旋动力学显示出过渡附近的临界速度变慢，并且磁序参数在过渡附近不断增长。有序状态。这些结果表明反铁磁转变是连续的，但随着有序温度的高斯分布而进行。由非弹性中子散射确定的对比热的磁性贡献同样显示出以120 K为中心的宽广特征。