Towards antiferromagnetic metal spintronics

PAPER: J. Basset, A. Sharma, Z. Wei, J. Bass, and M. Tsoi,

“Towards antiferromagnetic metal spintronics”,

Proc. of SPIE 7036, 703605 (2008).

ABSTRACT:

Spintronics is about control and manipulation of magnetic moments for new and improved functionality in electronic devices. The phenomenon of spin transfer emerged as a unique tool to control the magnetic state of a ferromagnet (F) with an electrical current. MacDonald and co-workers predicted that spin transfer could also occur in an antiferromagnet (AFM), where it might be even stronger under certain conditions. We recently showed that the exchange bias at an AFM/F interface, with AFM = FeMn and F = CoFe, could be either increased or decreased depending upon the polarity of the applied current. We attributed these changes to effects of the current on the AFM. Here we extend that study to a new AFM = IrMn and to a new F = Py = Ni_xFe_1-x with x ~ 0.2. Using exchange-biased spin-valves (EBSVs) of the form AFM/F(pinned)/Cu/F(free), where both Fs are the same alloy, we first compare data for F = CoFe with AFMs = FeMn or IrMn. The data for FeMn and IrMn are generally similar, with the current having clear effects upon the exchange bias, but little or none on the coercive field of the ‘free’ CoFe-layer. We then present data for F = Py with AFMs = FeMn or IrMn. With Py, the current generally affects both the exchange bias and the coercive field of the ‘free’ layer, in ways that we are not yet able to simply correlate with layer thicknesses or AFM.

This work was supported in part by NSF Grants DMR-06-45377 and DMR-08- 04126.