Large stable magnetic domains

Abstract

Large, thin-film single domain areas have been observed, in the absence of a bias field, in garnets with magnetization perpendicular to the film plane.1,2 The domain stability in the work by Krumme1 was attributed to a combination of low saturation magnetization and a low Curie temperature. Uchishiba2 relates the stability in his double layer system to appropriate anisotropy fields in one layer compared to the magnetization in the other layer. A more complete model for large domain stability in a bias field free environment is given in this work. Three distinct stability regimes are predicted by the model and all have been observed experimentally. Areas 3.5-cm in diameter have been made into stable single domains. This was achieved in a material showing a zero bias strip width of 4.5 μm. The single domain diameter was, therefore, 7500 times the equilibrium energy domain width. The technique developed and the model have led to a new means for observing magnetic defects. More importantly, it also offers a means for measuring the strength of the defects. Possible applications of the model are also discussed.

Fabrication and properties of spatial light modulator with magneto-optical Faraday effect

“…Pulliam [6] reported that the switching field of the pixel is determined by effective anisotropy Hk* in the localized regions where the magnetization reversal begins, and it is given by Hk* = 2 (Ku-Ks) / Ms where Ku is the magnetic anisotropy perpendicular to the film surface, Ks is the stress induced anisotropy and Ms is the saturated magnetization. As Ku includes the growth-induced anisotropy Ku g , the large switching field of the pixels may arise from Ku g appeared in Bi substituted LPE film growth [7].…”

Spatial Light Modulators For Laser Beam Control

“…Phase modulation and rapid modulation. The Magneto -optic SLM can true bipolar operation (without a bias switch rapidly (<1 microsecond) between two level) can be obtained by polarization transmittance states [18], i.e., it is a encoding.…”

“…The Magneto-optic SLM can switch rapidly (<1 microsecond) between two transmittance states [18], i.e., it is a binary modulator. In this sense it is very similar to the ferroelectric liquid crystal device.…”

Magneto-Optic/Eddy Current Imaging of Subsurface Corrosion and Fatigue Cracks in Aging Aircraft

“…The magneto-optic sensors used by PRi consist of a thin film of bismuth-doped iron garnet (Bi,Tm)3(Fe,Oa)5012 grown on a 3-inch diameter, 0.020 inch-thick substrate of gadolinium gallium garnet (000) [14][15][16]. These films exhibit three physical properties that are crucial for a practical magneto-optic/eddy current imaging instrument.…”