Spin-pumping into p-type diamond from NiFe

NV centers in diamond are promising candidates for quantum sensors and quantum information science [1]. In the quantum diamond devices, initialization of electron and/or nuclear spins is required, but it has not yet been demonstrated. Toward the electrical initialization, injection of polarized electron is important, because it may be used for it [2]. Here, we focus on a spin-pumping technique to demonstrate the spin-injection into diamond.
In this study, a NiFe and detector are fabricated on a p-type diamond. Under the ferromagnetic resonance of the NiFe, we observed various electromotive forces (EMFs) in detector that are similar with the previous study [3]. We used Ta and Pd as a detector. This is because they have opposite spin-Hall-angles [4]. The result shows that the EMF in Ta is opposite to that in Pd, which shows that a part of the EMFs originates the inverse spin-Hall effect. These results demonstrate spin-current injection into p-type diamond from NiFe.
[1] G. Balasubramanian, et al., Nat. Mater. 8, 383 (2009).
[2] T. Akiho, et al., Phys. Rev. B 87, 235205 (2013).
[3] N. Fukui, et al., Solid State Commun. 243, 44 (2016).
[4] M. Morota et al., Phys. Rev. B 83, 174405 (2011).