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Materials with Magnetic-X Effects
Published in Chen Wu, Jiaying Jin, Frontiers in Magnetic Materials, 2023
The magneto-optical recording integrates the optical recording and magnetic recording, with the high storage density, removability and nonvolatility functions that have developed as an industrially important information storage technique (Tsunashima, 2001). To qualify as a magneto-optical recording medium for massive application, the following criteria should be satisfied. Firstly, the magnetic anisotropy should be perpendicular to the film plane, exhibiting a rectangular hysteresis loop and high coercivity that drops sharply when illuminated with a focused laser beam. Secondly, high magneto-optical recording sensitivity (reduced laser recording power), large magneto-optical effect (large Faraday or Kerr angle) and low disk writing noise are required. Thirdly, satisfactory thermal stability, chemical stability and low-cost production are also necessary. There are three main types of magneto-optical recording materials including manganese-bismuth (MnBi) film (Furuya et al., 2016), amorphous rare-earth-transition metal (RE-TM) film (Murakami and Birukawa, 2003), and rare-earth iron garnet (Lomako, 2013; Nakamura et al., 2014).
A Survey of Experimental Methods: Physical Property Determination
Published in Paul Klocek, Handbook of Infrared Optical Materials, 2017
Magneto-optical spectroscopy employs a combination of a laser (of design relevant for the wavelength regime under study) with a high-field magnet. Fields up to about 20–30 T are available as stationary fields, and pulsed fields can be produced nondestructively to about 50 T (Miura et al. 1981). By the use of destructive methods [such as explosively driven magnetic flux compression techniques (Fowler et al. 1976)], fields in excess of 300 T, or 3 megagauss, have been obtained. Using solid-state lasers in the near-infrared and molecular gas lasers in the far-infrared, the most commonly used techniques for the study of magneto-optic effects are as follows: Magnetoreflection (Kido 1983)Magnetotransmission; Alfven wave propagation (Hiruma et al. 1983)Cyclotron resonance (Kido et al. 1981)Faraday rotation in spontaneously magnetic materials (Dillon 1958; Yang et al. 1980)
Magnetic recording
Published in David Jiles, Introduction to the Electronic Properties of Materials, 2017
Another area of interest in magnetic recording is that of magneto-optic devices. These make use of the Faraday and Kerr effects in which the direction of polarization of light is rotated in the presence of a magnetic field. In this way, two oppositely magnetized regions on a magnetic medium can be distinguished. The advantage of magneto-optical disks is that the storage density can be 1000-times greater than for floppy disks [13, 14], while access time for magneto-optic disks are 40–100 ms which are about 10-times faster than for floppy disks but are not yet competitive with access times for hard disks, which are typically 20–60 ms [14].
GdPtBi Heuslerene: mechanical stability, half-metallic, magneto-optic, and thermoelectric properties by DFT
Published in Philosophical Magazine, 2022
Farnaz Hosseinzadeh, Arash Boochani, Seyed Mohammad Elahi, Zohreh Ghorannevis
Magneto optic Kerr effect (MOKE) and magneto-optic (MO) are generally potent tools in ferromagnetic (FM) research. Extensive research has recently been conducted to investigate semiconductors with improved ferromagnetic properties, including the development of spintronic properties such as spin valves, spin diodes, magnetic sensors, logic devices, and optical switches. Thus, it can be used as a material for electronic device applications. Hence, materials with large magnetic moments can be a good candidate for research on magneto-optical properties and they may be used as an optoelectronic device. For these reasons, we are examining the effect of magneto-optics and magnetic properties. The main reasons for using magneto-optical phenomena in scientific research instruments are the characterisation of magnetic samples (high accuracy in measuring magnetic samples), the low cost of devices based on these effects, and the ability of light to scan a small area of magnetic material. Another reason is the low risk of utilising magnetic fields. The magneto-optic Kerr effect (MOKE) has attracted much attention in basic and applied research because it is very promising to investigate high-density storage systems. Recent detailed studies by Buschow, Reim, and Schoenes show that, properly stored in a magnetic material, digital information can be read using MOKE. Despite intensive experimental research, understanding the theory of MOKE leaves much to be desired.
Fabrication of ridge waveguide on the ion-implanted TGG crystal by femtosecond laser ablation
Published in Journal of Modern Optics, 2020
Jing-Yi Chen, Jie Zhang, Liao-Lin Zhang, Chun-Xiao Liu
Magneto-optical materials are critical for various optical devices such as optical isolators, optical circulators and optical modulators in the fields of fibre lasers, optical communications and so on [1,2]. As one of the most intriguing and commercialized magneto-optical materials, terbium gallium garnet (Tb3Ga5O12, TGG) crystal has attracted widespread attention because of its outstanding optical and magnetic properties in the visible and infrared spectral range [2]. The Verdet constant (describes the strength of the Faraday effect) and the thermal conductivity are superior in TGG crystal compared with magneto-optic glasses [3,4]. Specifically, the Verdet constant of the TGG crystal is 35 Rad T−1m−1 and thermal conductivity is 7.4 Wm−1K−1 [5,6]. Furthermore, TGG possesses low transmission loss, high laser damage threshold and low absorption coefficient [7,8]. By virtue of its advantages, TGG crystal has become a suitable candidate medium for creating Faraday effect devices. However, the traditional bulk Faraday isolators are hardly compatible with photonic integrated circuits [9]. In order to realize the integration, it is necessary to develop a waveguide-type optical device with host TGG crystal.
About Faraday rotation in bulk media, in a magneto-active layer and in a magneto-photonic crystal layer
Published in Journal of Modern Optics, 2019
A.H. Gevorgyan, S.S. Golik, T.A. Gevorgyan
Optical and magneto-optical properties of magneto-active layers and of one-dimensional magneto- photonic crystals (MPCs) are investigated from both experimental and theoretical standpoints. In particular, magneto-optical phenomena are now widely used as a research method for various problems on the structure of the matter. On the other hand, magneto-optical effects are very useful when designing sensitive magneto-optical filters, optical isolators, circulators, phase shifters, ultrasensitive biosensors, etc. Optical isolators based on Faraday rotation, in turn, are of importance in many applications, such as quality assurance of optical amplifiers, optical ring lasers, and optical communication systems. They are highly reliable and important tools for supporting advanced information technology and optical communication.