One of the cornerstone effects in spintronics is spin pumping by dynamical magnetization that is steadily precessing (around, for example, the
We use neutron scattering to show that ferromagnetism and antiferromagnetism coexist in the low T state of the pyrochlore quantum magnet
- NSF-PAR ID:
- 10199102
- Publisher / Repository:
- Proceedings of the National Academy of Sciences
- Date Published:
- Journal Name:
- Proceedings of the National Academy of Sciences
- Volume:
- 117
- Issue:
- 44
- ISSN:
- 0027-8424
- Page Range / eLocation ID:
- p. 27245-27254
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract z -axis) with frequencyω 0due to absorption of low-power microwaves of frequencyω 0under the resonance conditions and in the absence of any applied bias voltage. The two-decades-old ‘standard model’ of this effect, based on the scattering theory of adiabatic quantum pumping, predicts that component of spin current vector is time-independent while and oscillate harmonically in time with a single frequencyω 0whereas pumped charge current is zero in the same adiabatic limit. Here we employ more general approaches than the ‘standard model’, namely the time-dependent nonequilibrium Green’s function (NEGF) and the Floquet NEGF, to predict unforeseen features of spin pumping: namely precessing localized magnetic moments within a ferromagnetic metal (FM) or antiferromagnetic metal (AFM), whose conduction electrons are exposed to spin–orbit coupling (SOC) of either intrinsic or proximity origin, will pump both spin and chargeI (t ) currents. All four of these functions harmonically oscillate in time at both even and odd integer multiples of the driving frequencyω 0. The cutoff order of such high harmonics increases with SOC strength, reaching in the one-dimensional FM or AFM models chosen for demonstration. A higher cutoff can be achieved in realistic two-dimensional (2D) FM models defined on a honeycomb lattice, and we provide a prescription of how to realize them using 2D magnets and their heterostructures. -
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