Ultrahigh cooperativity interactions between magnons and resonant photons in a YIG sphere
Ultrahigh cooperativity interactions between magnons and resonant photons in a YIG sphere
复制标题
DOI：
10.1103/physrevb.93.144420
复制
发表时间：
2016-04-25
影响因子：
3.7
通讯作者：
Tobar, M. E.
中科院分区：
文献类型：
--
作者：
Bourhill, J.;Kostylev, N.;Tobar, M. E.
在10-30-GHz频率范围内，直径为5 mm的钇铁石榴石（YIG）球加载在一个圆柱形腔的共振光子模式的特点是作为一个功能的应用直流磁场在毫开尔文温度。光子模式主要局限于球体，并表现出大的模式填充因子相比，以前的实验，允许超强耦合的磁振子自旋波共振。对于15.5 GHz模式，光子和磁振子之间观察到的最大耦合为2g/2 pi = 7.11 GHz，对应于C = 1.51 +/- 0.47 x 10（7）的协同系数。复杂的修改，超越了一个简单的多振荡器模型，光子模式频率之间观察到0和0.1 T。在0.4和1 T之间，观察到简并共振光子模式与具有不同耦合强度的磁振子自旋波共振相互作用，表明由于YIG的回旋磁导率导致的时间反演对称性破缺。裸介质谐振器模式频率确定失谐磁振子模式，以显着更高的频率与强磁场。通过比较测量的模式频率在7 T与有限元建模，裸介电常数为15.96 +/- 0.02的YIG晶体已被确定在约20 mK。
Resonant photon modes of a 5-mm-diameter yttrium iron garnet (YIG) sphere loaded in a cylindrical cavity in the 10-30-GHz frequency range are characterized as a function of applied dc magnetic field at millikelvin temperatures. The photon modes are confined mainly to the sphere and exhibited large mode filling factors in comparison to previous experiments, allowing ultrastrong coupling with the magnon spin-wave resonances. The largest observed coupling between photons and magnons is 2g/2 pi = 7.11 GHz for a 15.5-GHz mode, corresponding to a cooperativity of C = 1.51 +/- 0.47 x 10(7). Complex modifications, beyond a simple multioscillator model, of the photon mode frequencies were observed between 0 and 0.1 T. Between 0.4 and 1 T, degenerate resonant photon modes were observed to interact with magnon spin-wave resonances with different coupling strengths, indicating time-reversal symmetry breaking due to the gyrotropic permeability of YIG. Bare dielectric resonator mode frequencies were determined by detuning magnon modes to significantly higher frequencies with strong magnetic fields. By comparing measured mode frequencies at 7 T with finite element modeling, a bare dielectric permittivity of 15.96 +/- 0.02 of the YIG crystal has been determined at about 20 mK.