Bi-YIG ferrimagnetic insulator nanometer films with large perpendicular magnetic anisotropy and narrow ferromagnetic resonance linewidth

Investigation of the Interface of Y3Fe5O12/Gd3Ga5O12 Structure Obtained by the Liquid Phase Epitaxy

“…Regarding to such an important characteristic as the Young modulus (Е), all mechanical calculations of YIG-based films till now (e.g., in Ref. [8]) were based on the experimental work in Ref. [55] and determined that Е = 200 GPa is good for bulk polycrystalline sample of YIG at the room temperature.…”

“…This intermediate layer, in which structure and chemical composition change from gadolinium gallium garnet to yttrium iron one, is also the source of mechanical stresses that, particularly, affects the value of magnetic anisotropy of YIG-based films. [6][7][8][9] Formation of the interface in traditional LPE technology associated with Y 3 Fe 5 O 12 /Gd 3 Ga 5 O 12 (YIG/GGG) garnet structures [1,3,5] occurs in the first moments of growth due to: etching by solution-melt (usually based on PbO-B 2 O 3 flux) of GGG substrate's surfaces, mutual incorporation of gadolinium and gallium ions into the growing YIG film, and, in contrary, yttrium and iron ions into the substrate. Because the process of growing is sufficiently long (from minutes to tens of hours depending on width of epitaxial layer) and occurs at relatively high temperatures (900…1000 °С), the continuous mutual interdiffusion of ions can take place during the growth of the film.…”

Strong Perpendicular Anisotropy and Anisotropic Landé Factor in Bismuth-Doped Thulium Garnet Thin Films

“…The method for obtaining a strong PMA effect in garnet films is to introduce a large uniaxial anisotropy, K u , composed of stress-induced perpendicular anisotropy K λ u and growth-induced anisotropy K g u , which are related to the lattice mismatch, magnetostriction constant, and interaction between the ions (Hansen and Witter, 1985). There are several ways to obtain ferrimagnetic garnet films with a strong PMA effect, such as doping with Bi (Hansen et al, 1983;Hansen and Krumme, 1984;Hansen and Witter, 1985;Soumah et al, 2018;Lin et al, 2020), introducing extra K g u , substituting other rare-earth elements (Tang et al, 2016;Avci et al, 2017;Wu et al, 2018), using a large magnetostriction constant to improve K λ u , or changing the substrate materials (Tang et al, 2016;Fu et al, 2017;Ciubotariu et al, 2019) to enlarge K λ u by creating a greater lattice mismatch. Ultrathin films manufactured in the GGG (111)/TmIG system exhibit the PMA effect, owing to the great negative magnetostriction constant of the TmIG (Tang et al, 2016;Vilela et al, 2020) compared to the YIG (Sokolov et al, 2016;Fu et al, 2017).…”

Growth parameters of Bi0.1Y2.9Fe5O12 thin films for high frequency applications

“…It has already been observed that substituting Bi/Ce for Y in YIG improves magneto-optical responsivity [13,[15][16][17][18][19][20][21]. In addition, Bi substitution in YIG (Bi-YIG) is known to generate growth-induced anisotropy, therefore, perpendicular magnetic anisotropy (PMA) can be achieved in Bi doped YIG, which is beneficial in applications like magnetic memory and logic devices [7,22,23]. Due to its usage in magnon-spintronics and related disciplines such as caloritronics, the study of fundamental characteristics of Bi-YIG materials is of major current interest due to their high uniaxial anisotropy and Faraday rotation [17,[24][25][26][27].…”