We study spin-photon coupling in cavity in the presence of relative phase shift between two ferromagnetic resonance driving forces. We show that the anticrossing gap can be manipulated by varying the relative phase. Increasing the phase difference leads to narrowing the anticrossing gap of hybridized modes and eventually to phase locked coupling at the value of relative phase of π. The FMR and cavity modes become phase locked and oscillate at the same frequency near the resonance frequency. Characteristic linewidth drop and transmission amplitude enhancement are demonstrated. The phase resolved spin-photon coupling can be used both for phase imaging and controlling coupling parameters.Strong interaction of light with matter in condensed matter systems paves way for exploring a wide range of different physical phenomena: starting from observation and even manipulation of matter by light in atomic scale and light manipulation to exploration of the polariton [1] in order to develop quantum information technology. Achieving strong coupling due to cooperative phenomena of spin ensembles [2, 3] triggered strong interest in strong magnon-photon interactions between magnetic materials with low dissipation and high quality microwave cavities [4][5][6][7][8][9][10][11][12]. Coherent coupling between single spin and microwave cavity photons [13], ferromagnetic magnon and a superconducting qubit [14] as well as cavity photons and magnons in magnetic materials [9-12] have been reported. Indirect coupling between spins, mediated by cavity, have been achieved for cavity [15] and circuit quantum electrodynamics [16,17]. In addition to widely used microwave transmission measurements of magnon-photon coupling at room temperature, electrical detection method has been recently demostrated by Hu's group [18]. Theoretically, the spin-photon coupling has been formulated by means of scattering theory [19] as well as simple semiclassical model [18]. The relevance of the classical picture to quantum mechanical picture has been discussed elsewhere [20]. It was demonstrated that, although the coupling does not affect the intrinsic Gilbert damping, the FMR linewidth (∆H) always increases [18] when FMR frequency approaches to resonance.To overcome the drawback of the linewidth broadening due to coupling induced extrinsic damping [18], while having strong coupling, we consider spin-photon coupling in cavity resonator when, together with the magnetic component of microwave field in the cavity, an additional local FMR driving force exists with a relative phase shift (Φ) between them. In Fig. 1 we show the schematic picture of the system under study. In this device the microwave signal from a broadband microwave generator "G" is directed via a coaxial cable to a rf power divider "D" [21,22], which coherently splits the microwave into two different beams. One of the beams then travels through a microwave phase shifter [21, 22] "Φ" by path "A" to an integrated [23] strip line on an insulator nonmagnetic layer. The YIG film is on top of the strip li...

We predict a magnetoresistance induced by the interfacial Rashba spin-orbit coupling in normal metal|ferromagnetic insulator bilayer. It depends on the angle between current and magnetization directions identically to the "spin Hall magnetoresistance" mechanism caused by a combined action of spin Hall and inverse spin Hall effects. Due to the identical phenomenology it is not obvious whether the magnetoresistance reported by Nakayama et al. is a bulk metal or interface effect. The interfacial Rashba induced magnetoresistance may be distinguished from the bulk metal spin Hall magnetoresistance by its dependence on the metal film thickness

The spin Hall effect and its inverse effect, caused by the spin orbit interaction, provide the interconversion between spin current and charge current. Since the effects make it possible to generate and manipulate spin current electrically, how to realize the large effects is an important issue in both physics and applications. To do so, materials with heavy elements, which have strong spin orbit interaction, have been examined so far. Here, we propose a new mechanism to enhance the spin Hall effect without heavy elements, \ie surface roughness in metallic thin films. We examine Cu and Al thin films with surface roughness and find that they give the spin Hall effect comparable to that in bulk Au. We demonstrate that the spin Hall effect induced by surface roughness has the side jump contribution but not skew scattering.Comment: 5 pages, 4 figure

We study dissipative spin-spin coupling in dispersive regime mediated by virtual photons in a microwave cavity. Dissipative coupling between magnetization of each magnetic material and the cavity photons is established by means of two phase shifted driving forces acting on each magnetization. We show that when only one of the magnetization is dissipatively coupled to the cavity, the cavity-mediated spin-spin coupling too, exhibits mode level attraction in the spectrum. By tuning the phase parameter at each ferromagnetic insulator we can shift the order of "dark" and "bright" collective modes with phase difference equal to 0 or π. Moreover, by selectively applying the phase shifted field it is possible to construct "dark" and "bright" collective modes with phase difference equal to ±π/2.