Devices that take advantage of spin currents for their special electronic properties are made up of multiple layers of materials. For the measurements in this research, a device was made up of yttrium iron garnet (YIG) and a normal metal separated by an antiferromagnetic (AF – a material whose magnetic moments are canceled) insulating layer. (The heat sink and heater allowed a temperature gradient (T) for the spin current generation). The introduction of the AF insulating layer amplifies the spin current (blue curve in right figure) as compared to the plain metal-YIG interface (red curve) by up to a factor of 10. In the absence of the ferromagnetic YIG substrate, the spin current disappears (black line). The data in the figure was for a platinum (Pt) metal layer; the data correlate the applied field (H) with the measured inverse spin Hall voltage (V).