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

2005: 1。本文利用布里渊光散射（BLS）技术，研究了室温下Co_<51>Al_<18>O_<31>溅射薄膜在高达6 kOe磁场下的超顺磁激发。我们可以观察到从0.5 kOe以下无序态的重阻尼光谱到4.5 kOe以上场致铁磁态的静磁自旋波（SW）光谱的瞬态行为。这是BLS对SPM激发的首次观测。我们还证实了偶极子耦合主导激励频率。我们计划研究SPM的低温激发。研究了室温下Co_<78>Al_<18>O_<18>, Co_<66>Al_<11>O_<23>和Co_<63>Al_<13>O_<24>铁磁性薄膜的磁常数，包括交换场H_<ex>。结合交换场和比电阻率，我们发现了电阻率ρ与交换率之间的平方反比规律。More e场H_<ex>: ρ_<Co>=22.1x H_<ex>^<-2> （μΩ.cm）。这里，H_<ex>是kOe单位。2006：我们认为平方反比定律是金属-非金属软磁颗粒膜的磁电特性特征。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SWs的BLS。我们准备好的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 >电影在这个研究。再一次，我们从SWs获得了BLS光谱，并确定了它们的频率作为磁场的函数。我们测定了Fe- al - o薄膜的交换场，并证实了ρ_<Fe>=30.3 × H_<ex>^<-2> （μΩ.cm）的平方反比定律。在这两年的项目中，我们获得了两个重要的和相当新的成果。(1)我们清楚地表明，在软磁纳米颗粒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）颗粒膜的交换场常数。少

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