Dipolar spin waves of lateral magnetic superlattices
Dipolar spin waves of lateral magnetic superlattices
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横向磁超晶格的偶极自旋波
DOI：
10.1103/physrevb.82.224417
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发表时间：
2010
影响因子：
3.7
通讯作者：
Saraiva P
中科院分区：
文献类型：
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作者：
Saraiva P
我们研究了异质结表面制作的镝和钴光栅的高频动力学特性。我们通过测量二维电子气中的光生电压和光生电阻来探测光栅的集体和局域自旋波模。磁激励通过其杂散磁场耦合到2DEG。我们执行的偶极交换自旋波作为微波功率，温度，所施加的磁场的倾斜角的函数的光谱，并通过改变结构和材料参数来改变偶极相互作用的强度。这些数据揭示了两种类型的自旋波。偶极磁化波通过条纹之间的静磁相互作用在光栅上传播。从第一性原理出发，导出了色散曲线的解析表达式，并得到了铁磁共振展宽的良好拟合。第二类是偶极边缘自旋波，在较低磁场下通过一系列尖锐的共振表现出来。这些波被限制在磁极表面附近，与相邻条纹的相互作用非常小。我们计算了量子化模式的本征频率，并得到了低场共振的定性解释。拟合产生镝的交换刚度常数的值。我们的实验表明，在混合磁-铁磁结构中的光电压测量为探测小磁体（10-500 nm）的自旋波提供了一种灵敏和非侵入性的工具。
We investigate the high-frequency dynamics of dysprosium and cobalt gratings fabricated at the surface of aheterojunction. We detect the collective and localized spin-wave modes of the grating by measuring the photovoltage and the photoresistance induced in the two-dimensional electron gas (2DEG). The magnetic excitations couple to the 2DEG through their stray magnetic field. We perform a spectroscopy of dipolar-exchange spin waves as a function of microwave power, temperature, the tilt angle of the applied magnetic field, and by varying the structural and material parameters to change the strength of dipolar interactions. The data reveal two types of spin waves. Dipolar magnetization waves propagate across the grating through the magnetostatic interaction between the stripes. We derive an analytical expression of their dispersion curve and obtain a good fit of the ferromagnetic resonance broadening from first principles. The second type is dipolar edge spin waves which manifest through a series of sharp resonances at lower magnetic field. These waves are confined near the pole surfaces and interact very little with neighboring stripes. We calculate the eigenfrequencies of the quantized modes and obtain a qualitative explanation of the low-field resonances. The fit yields a value of the exchange stiffness constant of dysprosium,. Our experiments show that photovoltage measurements in hybrid semiconductor-ferromagnetic structures provide a sensitive and noninvasive tool for probing the spin waves of small magnets (10–500 nm).
DOI：
--
发表时间：
2006
期刊：
--
影响因子：
--
作者：
Iroon Polytechniou-
通讯作者：
Iroon Polytechniou-