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Laser Spectroscopy of Fe-Co-Al-0 Granular Films

Fe-Co-Al-0 颗粒薄膜的激光光谱分析

基本信息

批准号：
17560586
负责人：
YOSHIHARA Akira
金额：
$ 2.24万
依托单位：
Ishinomaki Senshu University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

项目摘要

2005 :1. We have examined superparamagnetic (SPM) excitations in a sputtered Co_<51>Al_<18>O_<31> film by Brillouin light scattering (BLS) at room temperature in magnetic fields of up to 6 kOe. We could observe transient behaviors from heavily damped spectra in disorder state below 0.5 kOe to the magnetostatic spin-wave (SW) spectra in the field-induced ferromagnetic state above 4.5 kOe. This is the very first BLS observation of the SPM excitations. We also confirmed that dipole coupling dominates the excitation frequencies. We have a plan to investigate the SPM excitations al low temperatures.2. We examined BLS from SWs in ferromagnetic Co_<78>Al_<18>O_<18>, Co_<66>Al_<11>O_<23> and Co_<63>Al_<13>O_<24> films in magnetic fields of up to 4.0 kOe at room temperature, and determined the magnetic constants including the exchange field H_<ex> for each film. Combining the exchange fields and the specific resistivities, we found an inverse-square law between the reisitivity ρ and the exchang … More e field H_<ex> : ρ_<Co>=22.1x H_<ex>^<-2> (μΩ.cm). Here, H_<ex> is in kOe unit.2006 :We consider that the inverse-square law is a characteristic magneto-electric property of the metal-nonmetal soft magnetic granular films. We selected Fe-Al-0 films as another model material, and measured BLS from the SWs at room temperature. We prepared Fe_<83>Al_<19>O_8, Fe_<76>Al_<12>O_<12>, Fe_<64>Al_<10>O_<17> and Fe_<62>Al_<19>O_<19> films in this study. Again, we obtained BLS spectra from SWs and determined their frequencies as a function of the magnetic field. We determined the exchange fields, and confirmed the inverse-square law given by ρ_<Fe>=30.3 x H_<ex>^<-2> (μΩ.cm) for the Fe-Al-O films.In this two years project we have obtained two important and quite new results. (1) We have clearly shown that inter-granule exchange coupling really exists in soft ferromagnetic nano-granular films. (2) Now it is possible to determine the exchange field constant of the TM-Al-0 (TM=Fe, Co) granular films through resistivity measurement. Less

2005：1。我们在室温下、在高达 6 kOe 的磁场中通过布里渊光散射 (BLS) 检查了溅射 Co_<51>Al_<18>O_<31> 薄膜中的超顺磁 (SPM) 激发。我们可以观察到从低于 0.5 kOe 的无序状态下的重阻尼光谱到高于 4.5 kOe 的场感铁磁状态下的静磁自旋波 (SW) 光谱的瞬态行为。这是 BLS 首次观察到 SPM 激发。我们还证实偶极耦合在激励频率中占主导地位。我们计划研究低温下的SPM激发。 2．我们在室温下高达 4.0 kOe 的磁场中检查了铁磁 Co_<78>Al_<18>O_<18>、Co_<66>Al_<11>O_<23> 和 Co_<63>Al_<13>O_<24> 薄膜中 SW 的 BLS，并确定了每个薄膜的磁常数，包括交换场 H_<ex>。结合交换场和比电阻率，我们发现电阻率ρ与交换e场H_<ex>之间存在平方反比定律：ρ_<Co>=22.1x H_<ex>^<-2> (μΩ.cm)。这里，H_<ex>的单位是kOe。2006：我们认为平方反比定律是金属-非金属软磁颗粒薄膜的一个特征磁电特性。我们选择 Fe-Al-0 薄膜作为另一种模型材料，并在室温下测量了 SW 的 BLS。本研究制备了Fe_<83>Al_<19>O_8、Fe_<76>Al_<12>O_<12>、Fe_<64>Al_<10>O_<17>和Fe_<62>Al_<19>O_<19>薄膜。我们再次从 SW 获得了 BLS 谱，并确定了它们的频率作为磁场的函数。我们确定了交换场，并证实了Fe-Al-O薄膜的平方反比定律：ρ_<Fe>=30.3 x H_<ex>^<-2> (μΩ.cm)。在这两年的项目中，我们获得了两个重要且相当新的结果。 (1)我们清楚地表明，软铁磁纳米颗粒薄膜中确实存在颗粒间交换耦合。 (2)现在可以通过电阻率测量来确定TM-Al-0(TM=Fe,Co)颗粒薄膜的交换场常数。较少的