Sr$_{2-x}$La$_x$CoNbO$_6$中交换偏置效应与反位无序的相关性
Correlation between the exchange bias effect and antisite disorders in Sr$_{2-x}$La$_x$CoNbO$_6$
AI总结：
本研究分析Sr$_{2-x}$La$_x$CoNbO$_6$双钙钛矿的交换偏置效应，发现La掺杂引入的反位无序通过改变磁畴尺寸、磁相互作用比例及界面自旋弛豫特性调控交换偏置，建立了二者的关联。
摘要：
我们通过对场冷磁化等温线（M--H）和训练效应的详细分析，揭示了La掺杂及由此产生的反位无序对Sr$_{2-x}$La$_x$CoNbO$_6$（$x=$ 0, 0.2）双钙钛矿样品中交换偏置（EB）机制的影响。冻结温度的场依赖关系偏离了Gabay-Toulouse（GT）线和de Almeida-Thouless（AT）线，分析表明$x=$ 0的样品遵循不同的普适类，其冻结自旋具有中等各向异性。有趣的是，我们发现由于铁磁（FM）畴尺寸增大[团簇玻璃（CG）畴尺寸减小]，$x=$ 0.2样品中的EB效应被显著抑制，这减小了导致EB的有效无序界面。La掺杂和外加磁场引起的FM、AFM和类CG相互作用的比例变化，对调控这些样品中的EB效应至关重要。此外，训练效应测量显示M--H回线的左右支偏移不等，且它们随磁场循环次数（$n$）的演化规律不同。分析表明，在无序界面处，可旋转自旋的弛豫速度比冻结自旋快约一个数量级。我们发现这些样品中观测到的EB效应与反位无序之间存在可能的相关性。
英文摘要：
We unravel the effect of La substitution and hence antisite disorders on the exchange bias (EB) mechanism in Sr$_{2-x}$La$_x$CoNbO$_6$ ($x=$ 0, 0.2) double perovskite samples using the detailed analysis of the field cooled magnetization isotherms (M--H) and training effect. The field dependence of the freezing temperature deviates from both Gabay-Toulouse (GT) and de Almeida-Thouless (AT) lines and the analysis suggests that the $x=$ 0 sample follows a different universality class with moderate anisotropy in the frozen spins. Interestingly, we find that the EB effect is significantly suppressed in the $x=$ 0.2 sample due to increase [decrease] in the size of ferromagnetic (FM) [cluster glass (CG)] domain, which reduces the effective disordered interface responsible for the EB. The changes in fraction of FM, AFM, and CG like interactions with the La substitution and applied magnetic field are found to be crucial in governing the EB effect in these samples. Further, the training effect measurements show the unequal shift in the left and right branches of the M--H loops and their different evolution with the field cycles ($n$). The analysis reveals that the rotatable spins relax approximately one order of magnitude faster than the frozen spins at the disordered interface. We find a possible correlation between the observed EB effect and the antisite disorders in these samples.
机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。
