On April 23, we have the pleasure to welcome Yan Wen from King Abdullah University of Science and Technology (KAUST), Saudi Arabia. He makes actually his PHD supervised by Xixiang Zhang in collaboration with Aurélien Manchon. He will give us a seminar which will take place at SPINTEC 434A at 14:00.

Spin Transport in Metallic Antiferromagnets IrMn

Pure spin current will play an important role in the next generation spintronics devices and applications for their high efficiency. One of the crucial issue is that how to effectively inject the spin current from a generator (one material) to a receptor (another material). In addition to the rapid decay of the spin current when it traverses in a material, another key factor is that its transmission from the generator to the receptor will be further limited by the spin-mixing conductance at the interface.

It has been demonstrated that the transmission of the pure spin current across the interface of two materials can be greatly enhanced by intervening an antiferromagnetic layer between the generator and receptor. Both conducting and insulating antiferromagnetic materials have been exploited to unlock the underlying physics associated with the enhancement of the spin current transmission through the antiferromagnetic layer through spin pumping or spin Seebeck effect.

Here, we report the measurement the spin orbit torques in Ta/IrMn/Cu/Py system by using the second harmonic methods. I will then present a systematic investigation on the spin conductivity by tuning the thickness of IrMn and varying temperature of measurements. The significant enhancement of spin conductivity has been observed in the samples with 1 and 1.5 nm IrMn. We propose that the spin accumulation generated in Ta through spin Hall effect would partially convert into magnonic spin current at the interface of Ta/IrMn. The spin current is therefore transported from Ta to Py through AFM magnons and electrons in IrMn layer.