We report some spintronic properties including Gilbert damping, spin Seebeck effect, and magnon–photon coupling for a spinel ferrite Mg_0.5−δMn_0.5Fe₂O₄ (MMFO). Bulk single crystals of MMFO (δ ≈ 0.12) grown by a floating zone method are well insulating and soft ferrimagnetic with saturation magnetization of 0.3 T at room temperature. The measurement of ferromagnetic resonance yields the Gilbert damping of ∼0.01 and the relatively large Gilbert damping is consistent with a small spin Seebeck coefficient (∼1 × 10⁻⁸ V/K) observed in Pt/MMFO structure. Nevertheless, coupling between excited magnons in MMFO and microwave photons in a split-ring resonator is clearly observed and the magnon–photon coupling is estimated to be even stronger than typical coupling strength reported for yttrium iron garnets.

中文翻译：

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具有大吉尔伯特阻尼的尖晶石铁氧体中的 Magnon-Photon 耦合

我们报告了尖晶石铁氧体 Mg _{0.5− δ} Mn _0.5 Fe ₂ O ₄ (MMFO) 的一些自旋电子特性，包括吉尔伯特阻尼、自旋塞贝克效应和磁振子-光子耦合。通过浮区法生长的 MMFO 块状单晶 ( δ ≈ 0.12) 具有良好的绝缘性和软亚铁磁性，室温下饱和磁化强度为 0.3 T。铁磁共振的测量产生了约 0.01 的吉尔伯特阻尼，并且相对较大的吉尔伯特阻尼与小自旋塞贝克系数（~1 × 10 ^-8V/K) 在 Pt/MMFO 结构中观察到。尽管如此，可以清楚地观察到 MMFO 中激发的磁振子和裂环谐振器中的微波光子之间的耦合，并且估计磁振子-光子耦合甚至比报道的钇铁石榴石的典型耦合强度还要强。