## 1 Introduction  
Magnetic garnets are essential components in a variety of bulk and thin film devices that require magnetic insulators. Initial experiments in magnonics were inspired by radar and microwave applications and were conducted with bulk yttrium iron garnet (YIG) crystals [1; 2]. In the past, bulk YIG crystals were utilized to explore magnonics on the micrometer to millimeter length scales required for microwave devices [3]. Presently, yttrium iron garnet (Y\({}_{3}\)Fe\({}_{5}\)O\({}_{12}\), YIG) has been used for spintronics [4; 5; 6; 7]. Spintronics applications that employ yttrium iron garnets emerged in 2010 and 2011 [8]. This interest is based on the fact that YIG materials have two important characteristics; namely, they have relatively low intrinsic damping \(a_{o}\) = 3 \(\times\) 10\({}^{-5}\)[6; 9] and electrically insulating [6; 8]. Low damping in YIG is essential for the construction of magnonic logic devices to transport, store, and process microwave and digital information. This minimal damping is very desirable for a variety of applications, such as spin-torque oscillators and spin-wave-based logic circuits [8]. Recent spintronics research has emphasized the transfer of spin information through spin-wave or magnon excitations in magnetic insulators [10]. Spintronic phenomena generate, manipulate, and detect spin-polarized charge carriers [2]. Additionally, YIG has the low infrared absorption, high Verdet constant, and extremely low damping that needed for applications such as Faraday rotators, isolators, and sensors [7]. The development of YIG-based spintronics necessitates YIG thin films with a nanometer-scale thickness and minimal damping. Unlike bulk crystal applications, thin film devices rely on interactions across the interface; consequently, surface properties (such as topology and magnetism) are crucial [7]. Extensive attention has been paid to the formation of micron or submicron-thick YIG films and the growth of nanometer-thick YIG films in the context of YIG research development [6]. In addition, the production of YIG films with superior structural and magnetic properties has the potential to be utilized to integrate spintronic, magnonic, and magneto-optical systems [2]. For magneto-optical activity, YIG is very transparent at near-IR communication wavelengths [11]. For magneto-optical devices, the Y is partly substituted by rare earth, which can boost the Faraday rotation by an order of magnitude [11; 12]. For example, cerium-doped YIG is a promising 1550 nm isolator material due to its high magneto-optical properties, indicated by the Faraday rotation divided by the optical absorption, and this is similarly observed in optical isolators comprised of Ce:YIG [12]. YIG can be synthesized using several techniques, including pulsed laser deposition (PLD) [2; 8; 11; 12; 13; 14; 15; 16; 17], molecular beam epitaxy (MBE) [18; 19], liquid phase epitaxy (LPE) [17; 20; 21; 22; 23; 24; 25], radio frequency (RF) magnetron sputtering [6; 26; 27; 28], ion beam sputtering [29; 30], chemical vapor deposition (CVD) [31], sol-gel [32; 33; 34], metal-organic decomposition (MOD) [35], etc. Pulsed laser deposition (PLD) is a typical method for the development of oxide thin films [7]. Nevertheless, systematic studies of YIG development and the association between the structural and magnetic properties are limited [7]. High-quality YIG thin films can be fabricated on a gadolinium gallium garnet (GGG), yttrium aluminum garnet (YAG) single crystal, silicon (Si), and gallium arsenide (GaAs) and be doped with rare earth elements to control the ferrimagnetic resonance (FMR) linewidth and for other applications [36; 37]. GaAs substrate is popular in conventional complementary metal-oxide-semiconductor (CMOS) applications because it has excellent charge carrier mobility and a broad band gap. In the example of germanium epitaxial films on GaAs substrates, the electrons recombine with valence band holes at a 0.8 eV energy level [38].