The elements of a microwave extraction device consist of: a microwave generator (known as magnetron), a waveguide used to distribute the microwaves, an applicator (where the sample to be extracted is loaded) and a circulator (i.e., a fan-shaped blade). This leads to a better recoding performance since the noise will be much lower compared with crystalline media which happens to be the cause of wall pinning and non-uniformity of the magnetization distribution ( Kravets et al., 2009). Due to the absence of grain boundaries in amorphous films, the domain walls can move readily under the presence of an external field. Their advantages compared to polycrystalline materials led to the technical breakthrough of RETM layers in the field of MO data storage. Amorphous layers have no grain boundaries and composition can be varied continuously. Figure 1 illustrates a typical diagram of FeTbCo/Co-Ag/HfO 2 multilayer sample which is deposited on a glass slide substrate ( Kravets et al., 2009). Amorphous layers can be prepared by rapid quenching from a liquid phase, evaporation, or sputtering and show a 5–15% lesser density than their crystalline counterparts, depending on composition and preparation conditions ( Klahn et al., 1990). These alloys exhibit very good recording properties such as high carrier-to-noise ratio (CNR), a good squareness of the hyteresis loop, and low required write/erase laser powers and fields ( Buschow et al., 2012). In current MO recording technology, the storage medium is amorphous rare-earth (RE) elements doped transition metal (RETM) alloys such as FeTbCo, CoDyFeO thin films ( Mohammadifar et al., 2014 Kravets et al., 2009). Ferrites, rare-earth (RE) garnets, and RE transition metal amorphous thin films are commonly considered for high density storage medium in modern MO recording techniques ( Mohammadifar et al., 2014). Data processing information technology as well as CAD/CAM computer systems widely use the high density digital magnetic and magneto-optical (MO) storage devices such as deflectors, modulators, switches, diodes, circulators, optical signal filters, displays, and magnetic field sensors ( Buschow et al., 2012 Mohammadifar et al., 2014).
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