Detection of weak (∼0.5-300 nT), low frequency (5-100 Hz) magnetic fields at room temperature by kilohertz modulation of the magneto-optical hysteresis in rare earth-iron garnet films

被引：14

作者：

Hafez, J. M. ^{[1
]}

Gao, J. ^{[1
]}

Eden, J. G. ^{[1
]}

机构：

[1] Univ Illinois, Dept Elect & Comp Engn, Lab Opt Phys & Engn, Urbana, IL 61801 USA

来源：

APPLIED PHYSICS LETTERS | 2007年 / 90卷 / 13期

关键词：

D O I：

10.1063/1.2713144

中图分类号：

O59 [应用物理学];

学科分类号：

摘要：

Periodic magnetic fields with frequencies in the 5-100 Hz range and peak strengths as low as 0.5 nT have been detected at 300 K by modulating at kHz rates the magneto-optical response of epitaxial (Tm,Bi)(3)(Ga,Fe)(5)O-12 rare earth-iron garnet films at lambda=532 nm. By exploiting the similar to 1 degrees/mu T slope of the magneto-optical transition region between the two magnetization states of these low coercivity (< 0.5 mT) films, sub-nT field strengths can be measured by upconverting the detection process into the kHz domain. The domain wall velocities are measured to be 3-30 m/s for modulation frequencies in the 0.3-10 kHz interval, and the noise generated by wall motion appears to be the primary barrier to further reductions in the detection sensitivity floor. Films with thicknesses of 2-4 mu m and mean domain widths of 3-6 mm exhibit figures of merit (Theta/alpha) of similar to 3 degrees-8.5 degrees at 532 nm. Imaging of mesoscopic magnetic particles is demonstrated with a spatial resolution of < 300 mu m. (c) 2007 American Institute of Physics.

引用

页数：3