Has long-distance spin-superfluid transport been demonstrated? · revision history

Revision 2

Accepted · core change · record

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Title · changed
Revision 1: Has long-distance spin-superfluid transport been demonstrated
Revision 2: Has long-distance spin-superfluid transport been demonstrated?
Plain
In magnets whose spins lie in a plane, a steady twist of the spin direction should carry spin current with little loss, decaying only slowly with distance, like a superfluid. Some experiments claim this, and magnon condensation in yttrium iron garnet is established, but other explanations of the signals remain.
Precise · changed · core
Revision 1: Spin superfluidity predicts a nonlocal spin signal decaying algebraically, $\sim 1/(L + L_0)$, instead of exponentially, $\sim \exp(-L/\lambda)$, and a critical spin current. Determine whether claimed observations in spin-flop Cr2O3 (Yuan et al. 2018), the graphene quantum Hall antiferromagnet (Stepanov et al. 2018) and magnon condensate supercurrents in YIG (Bozhko et al. 2016) show superfluid spin transport, by measuring the distance dependence and a critical current in a single device free of thermal artifacts. An answer is yes or no.
Revision 2: Spin superfluidity predicts a nonlocal spin signal decaying algebraically, $\sim 1/(L + L_0)$, instead of exponentially, $\sim \exp(-L/\lambda)$, and a critical spin current. Determine whether claimed observations in spin-flop $\mathrm{Cr_2O_3}$ (Yuan et al. 2018), the graphene quantum Hall antiferromagnet (Stepanov et al. 2018) and magnon condensate supercurrents in YIG (Bozhko et al. 2016) show superfluid spin transport, by measuring the distance dependence and a critical current in a single device free of thermal artifacts. An answer is yes or no.
Settled by
A nonlocal measurement over a range of injector-detector distances in one device showing algebraic decay and a critical current, with thermal spin Seebeck backgrounds excluded.
Kind
well-posed
Answer type
yes-no
References
(empty)
Literature status
contested
Status note
(empty)
Posed since
(empty)

Decisions