Anomalous subsidiary absorption in single‐crystal YIG and evaluation of spin‐wave linewidth
Anomalous subsidiary absorption in single‐crystal YIG and evaluation of spin‐wave linewidth
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DOI：
10.1063/1.325816
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发表时间：
1979-11
影响因子：
3.2
通讯作者：
C. Patton;W. Jantz
中科院分区：
文献类型：
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作者：
C. Patton;W. Jantz
对高质量钇铁石榴石单晶的辅助吸收自旋波不稳定阈值的测量表明，在Hc处蝴蝶曲线最小值以下数百Oe的场间隔内，异常结构出现。这种测量现在已经扩展到覆盖整个蝴蝶曲线的球体和板样。在结构区的低场端，随着静场H减小到“扭结”场H 'c， hcrit迅速增加。随着H的进一步减小，hcrit的增加更加缓慢。在H 'c处，反射功率的性质发生了急剧变化，从逐渐增加到阈值处的突然跳跃。理论分析表明：(1)自旋波在Hc处的不稳定性是指极性角ϑk为22°的自旋波，而不是通常引用的35°。(2)零波数（k=0）模不稳定性的场间隔不仅限于H > Hc，而且在很大范围内延伸到H 'c。(3) H 'c处的扭结对应于…
Measurements of the subsidiary absorption spin‐wave instability threshold hcrit in high‐quality single crystals of yttrium iron garnet reveal anomalous structure over a field interval extending several hundred Oe below the butterfly curve minimum at Hc. Such measurements have now been extended to cover the entire butterfly curve for sphere and plate samples. At the low‐field end of the structure region, hcrit increases rapidly as the static field H is decreased to a ’’kink’’ field H′c. As H is reduced further, the increase in hcrit is much more gradual. The nature of the onset changes drastically at H′c, from a gradual increase to an abrupt jump in reflected power at threshold. Theoretical analysis of the data shows: (1) The instability at Hc is for spin waves with a polar angle ϑk of 22° rather than the 35° value often cited. (2) The field interval for the instability of zero wave number (k=0) modes is not confined to H≳Hc, but extends over a wide range down to H′c. (3) The kink at H′c corresponds to an ...