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Thin Films for Electronic, Spintronics, and Optical Applications
Published in Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu, Thin Film Coatings, 2022
Fredrick Madaraka Mwema, Tien-Chien Jen, Lin Zhu
These features of magnetic garnets make them suitable for applications in the spintronic and photonic devices. These garnets are artificial layers with general formula of X3Fe5O12, where X can be Y, Bi, Tm, Yb, Er, Gd, Tb, Dy, Ho, Sm, Eu, or other rare-earth elements [17,18]. Iron garnets possess superior properties in many aspects as compared to magnetic metals or other magnetic insulators, particularly for applications in spintronic and photonic devices. Yttrium Iron Garnet (YIG) thin films with ultra-low damping (α) on gadolinium gallium garnet (GGG) substrates and PMA rare-earth iron garnet, doped-YIG, and pure-YIG thin films on appropriate non-magnetic garnet substrates can be fabricated using liquid phase epitaxy (LPE), pulsed laser deposition (PLD), and magnetron sputtering. YIG is a magnetic garnet, possessing the lowest α value so far on the earth among all discovered or synthesised materials.
Magnetic Ceramics
Published in Lionel M. Levinson, Electronic Ceramics, 2020
Microwave frequencies demand high-resistivity ferrites, as one can infer from our previous discussion of the frequency dependence of losses. Mn-Zn ferrites are not used here for that purpose. Nickel ferrites, Mg-Mn ferrites, and, more recently, the garnets have been used for microwave applications. The original material for garnets was YIG (yttrium-iron-garnet, Y3Fe5O12). Many substituted garnets have been used, such as Al3+ substitution to lower the saturation for lower microwave frequencies. The rare earths used have been extended to Sm and many others. As in recording heads, hot-pressed and single-crystal ferrites have been produced. To keep the resistivity high in microwave ferrites, excess Fe is avoided to eliminate Fe2+. In many instances, the Fe2O3 mole percentage is lower than 50%. Recently, garnets have also been used as a matrix for magnetic bubbles, which we will describe later.
Use of Rare Earth Materials in mm-Wave Microwave Systems and Sensors
Published in A. R. Jha, Deployment of Rare Earth Materials in Microware Devices, RF Transmitters, and Laser Systems, 2019
Y oxide is widely deployed for various commercial and industrial applications. It is used to manufacture YIG, which is best suited for microwave and low-frequency mm-wave filters in applications where a sharp cutoff performance in the stop band region is the main requirement. YIG is considered a hard-ceramic material, which is best suited for ultrasonic transmitters and transducers. In case of such transducers, the electrode materials and dimensions of the electrodes are of critical importance. Transducer designers face problems particularly in impedance matching from electrode to piezoelectric material. Note that optimum impedance matching is essential, if low input VSWR and minimum transducer insertion loss are the main requirements.
Preparation and properties of a left-handed metamaterial composite
Published in Philosophical Magazine Letters, 2019
Haiyan Li, Yuheng Guo, Zhenhai Li
Firstly, YIG (Y3Fe5O12) powders were prepared by the solid-state reaction method. Fe2O3 and Y2O3 were mixed in a molar ratio of 5:3, ball milled for 5 h and sintered at 1000°C for 8 h. Secondly, the YIG samples synthesised with different mass percentages of Ag (5, 10, 25 and 50 wt%) and labelled as YA-5, YA-10, YA-25, YA-50. Finally, the mixtures were well-grounded in a planetary ball mill for 8 h, pressed into green bodies using 35 Mpa of pressure, and sintered at 1200°C for 1 h.