Abstract In this study, lutetium iron garnet (Lu3Fe5O12; LuIG) thin films have been grown on Y3Al5O12 (1 1 1) substrates by a pulsed laser deposition and are co-substituted with strong magnetically anisotropic ions of Co2+ and nonmagnetic ones of Si4+. LuIG is a garnet-structured ferrimagnet with an exceptionally low Gilbert damping constant as 10−5. The substitution of Co2+ and Si4+ induces a chemical disorder and competing antiferromagnetic and ferromagnetic interactions, which induce a spin glass behavior. When the Co–Si substitution ratio is increased, a spin-freezing behavior is observed below the spin-freezing temperature TG = 190–220 K of the Lu3Fe4Co0.5Si0.5O12 film; this indicates the presence of a cluster glass phase. The film demonstrates a characteristic memory effects in the temperature range 120–180 K, which are below TG; this reveals the presence of a metastable magnetic state in the multi-valley energy landscape with shallow activation energy barriers. Ferromagnetic resonance measurements confirm increased perpendicular anisotropy energy induced by Co substitution and spin-wave characteristics including the inverse spin Hall effect voltage (VISHE). Lu3Fe5-2xCoxSixO12 films show an increase in damping and a decrease in VISHE at the cryogenic temperature, which are attributed to the impurity relaxation mechanism. Therefore, the Co- and Si-substituted films exhibit strong spin-wave damping at a low temperature, which reflects the spin-freezing dynamics of cluster glass behaviors.

中文翻译：

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Co-和Si-取代石榴石铁氧体薄膜中的高温自旋簇玻璃行为

摘要 在这项研究中，镥铁石榴石 (Lu3Fe5O12; LuIG) 薄膜已通过脉冲激光沉积在 Y3Al5O12 (1 1 1) 衬底上生长，并被 Co2+ 的强磁各向异性离子和 Si4+ 的非磁性离子共同取代。LuIG 是石榴石结构的亚铁磁体，其吉尔伯特阻尼常数非常低，为 10-5。Co2+ 和 Si4+ 的取代诱导了化学无序和竞争性反铁磁和铁磁相互作用，从而诱导了自旋玻璃行为。当 Co-Si 取代比增加时，在 Lu3Fe4Co0.5Si0.5O12 薄膜的自旋冻结温度 TG = 190-220 K 以下观察到自旋冻结行为；这表明存在簇状玻璃相。该薄膜在低于 TG 的 120-180 K 温度范围内表现出特征记忆效应；这揭示了在具有浅激活能垒的多谷能量景观中存在亚稳态磁态。铁磁共振测量证实了由 Co 取代和自旋波特性引起的垂直各向异性能量增加，包括反自旋霍尔效应电压 (VISHE)。Lu3Fe5-2xCoxSixO12 薄膜在低温下表现出阻尼增加和 VISHE 降低，这归因于杂质弛豫机制。因此，Co 和 Si 取代的薄膜在低温下表现出很强的自旋波阻尼，这反映了团簇玻璃行为的自旋冻结动力学。铁磁共振测量证实了由 Co 取代和自旋波特性引起的垂直各向异性能量增加，包括反自旋霍尔效应电压 (VISHE)。Lu3Fe5-2xCoxSixO12 薄膜在低温下表现出阻尼增加和 VISHE 降低，这归因于杂质弛豫机制。因此，Co 和 Si 取代的薄膜在低温下表现出很强的自旋波阻尼，这反映了团簇玻璃行为的自旋冻结动力学。铁磁共振测量证实了由 Co 取代和自旋波特性引起的垂直各向异性能量增加，包括反自旋霍尔效应电压 (VISHE)。Lu3Fe5-2xCoxSixO12 薄膜在低温下表现出阻尼增加和 VISHE 降低，这归因于杂质弛豫机制。因此，Co 和 Si 取代的薄膜在低温下表现出强烈的自旋波阻尼，这反映了团簇玻璃行为的自旋冻结动力学。