> Would it make electronics cheaper, smaller, more efficient As the name implies, it uses transport of spin rather than electrons themselves. The electrons may

> Would it make electronics cheaper, smaller, more efficient As the name implies, it uses transport of spin rather than electrons themselves. The electrons may not move at all (you can have a spin current with no electric current at all). So it'd no longer be electronics. The current premise is more dense memory devices with lower power consumption. > This seems like an eminently testable thing- just take a semiconductor, put it in contact with something else, put a, uh, spin current (layman!) through them and check for impedance. What hilariously ignorant mistake am I making? Well, where do I start? Think about these: how do you generate a spin current? How much is it? How do you measure it? (hint: no, there is no such thing as spinmeter) How do you store/switch/manipulate bits? How does it effect magnetization, temperature, electric current, chemical potential? (these are all intricately coupled things) What kind of spin waves is it going to generate? Can you treat them as quasi particles? (magnons) Will there be a flow of magnons? What are the transport properties and how does an interface affect it (it's not easy to isolate and measure only a single transport coefficient in practice)? What is your order parameter? Are we talking about a ferromagnet, antiferromagnet or ferrimagnet? Are they interfaced? What are the transport properties of your interface? What is your Landau free energy (from which you can calculate effective field or ground state)? Which phase of matter are you in? Helical phase? Skyrmion crystal phase? Canted/polarized phase? What is your geometry? What kind of stray field does it generate? What are your anisotropies? Does your system have a strong spin-orbit copuling? What is your overall spin transfer torque? How do all these depend of temperature / thermal fluctuations? etc etc etc. And keep in mind that almost all the physical observables we're talking about are really really really tiny. We're talking about quantum mechanical effects. I hope by now it is clear that you have to come up with an "impedance" on your own tailored to your system, taking all the relevant physical aspects of your system into account (which requires a good background in condensed matter physics). There is no generic "impedance" of "spinmeter" that will work in any situation. And generally, the issue is not measuring spin current or transport properties in an existing system. And you certain don't want to make devices randomly and measure its properties until something nice comes out miraculously: you have to "engineer" the desired properties (which typically requires very specific conditions), from ground up. So it's a little different from connecting a lamp and a resistor to a battery and see whether it lights up or not. Suffice it to say that it's more complicated than your average high school science experiments.