Synthesis of Bi–Lu-Substituted Iron Garnet Films for Visualization of Magnetic Flux in High-T_cSuperconductors

Abstract

In order to visualize the magnetic flux that penetrates into high-T c superconductors with high spatial resolution, epitaxial growth of the in-plane magnetic Bi-Lu-substituted iron garnet films was investigated. The ratio of increments of Faraday rotation to magnetic field increased to À13 deg/(cmÁOe) by Bi and Ga substitutions. The as-grown films showed a perpendicular magnetic anisotropy. The appropriate conditions for annealing treatments that change the perpendicular magnetic anisotropy into an in-plane magnetic anisotropy were investigated. Then, the annealed (BiLu) 3 (FeGa) 5 O 12 film clearly showed a high resolution image of the magnetic flux that penetrates into the NdBa 2 Cu 3 O 7À high-T c superconductor at temperatures between 5 K and 100 K, and the behavior of the magnetic flux penetrating the microcracks less than 5 m in width was successfully captured; the magnetic flux depends on external magnetic field and temperature.

Highly bismuth-substituted, record-performance magneto-optic garnet materials with low coercivity for applications in integrated optics, photonic crystals, imaging and sensing

“…However, the magnetization vectors of the films on both substrate types also had a perpendicular component, which resulted in the observations of maze-type magnetic domain patterns by polarization microscopy and also using magnetic force microscopy (NT-MDT Nova Scanning Probe Nanolaboratory). Within the linear magnetization range, a rather high Faraday-effect magnetic field sensitivity (the ratio of increments of Faraday rotation to magnetic field) of up to 42.8 °/(cm·Oe) was measured at 635 nm, which even exceeds the previously-reported value of 13 °/(cm·Oe) measured in epitaxial (BiLu) 3 (FeGa) 5 O 12 films obtained by LPE [22]. The domain structures observed in our garnet and garnet-oxide composite thin films in the absence of externally applied magnetic fields are shown in Fig.…”

“…This work is devoted to the synthesis and characterisation of highly Bi-substituted lutetium iron garnet thin films of composition type (BiLu) 3 (FeAl) 5 O 12 featuring a strong in-plane magnetization component and magnetically-soft switching behavior. Previous work on the synthesis of monocrystalline films of a similar composition type using a different technology has been reported by Adachi et al in 2002 [22]. They reported on the preparation of (BiLu) 3 (FeGa) 5 O 12 garnet films by the liquid-phase epitaxy (LPE) technique, and their monocrystalline layers were also postannealed at high temperatures to obtain the in-plane magnetic anisotropy.…”

Influence of Substrate Stage Temperature and Rotation Rate on the Magneto-Optical Quality of RF-Sputtered Bi2.1Dy0.9Fe3.9Ga1.1O12 Garnet Thin Films

“…Bismuth (Bi)-substituted magneto-optical (MO) garnet materials are very attractive for use in various technological applications such as magnetic memory, magnetoplasmonic devices, magneto-optic sensors, lightwave polarization controllers, and MO spatial or temporal light modulators [1][2][3][4][5][6][7][8][9][10][11]. They possess record-high Faraday or Kerr effects simultaneously with low optical losses in parts of the visible and near-infrared regions and are starting to become highly sought after for the development of cost-effective and reliable photonic devices and sensors.…”

In-plane magnetic anisotropy of (111) and (100) garnet film prepared for magneto-optical indicator

“…The MO imaging is powerful technique for the realtime observation when applied magnetic fileds and temperatures are continuously changed. Magnetic garnets have an advantage for the observation of magnetic flux in high T c superconductor because the Curie temperature is more than 500 K. We recently reported the synthesis of Bi-Lu-substituted iron garnet film with in-plane magnetic anisotropy [5]. Because of no appearance of perpendicular magnetic domain, an in-plane magnetic film is considered to realize high spatial resolution less than 1 mm and the response time to the field change is expected to be several nanoseconds.…”

“…For the growth of in-plane magnetic film, it is important that those anisotropy energies are totally treated. In this report, we focused on the difference of in-plane magnetic anisotropy of (1 1 1) and (1 0 0) (BiLu) 3 (FeGa) 5 O 12 (BLIG) film. Bi enhances the MO effect in visible light region.…”