  A micro-patterned spin Seebeck device is fabricated using an on-chip heater.
Current is driven through a Au heater layer electrically isolated from a
bilayer consisting of Fe$_3$O$_4$ (insulating ferrimagnet) and a spin detector
layer. It is shown that through this method it is possible to measure the
longitudinal spin Seebeck effect (SSE) for small area magnetic devices,
equivalent to traditional macroscopic SSE experiments. Using a lock-in
detection technique it is possible to more sensitively characterize both the
SSE and the anomalous Nernst effect (ANE), as well as the inverse spin Hall
effect in various spin detector materials. By using the spin detector layer as
a thermometer, we can obtain a value for the temperature gradient across the
device. These results are well matched to values obtained through
electromagnetic/thermal modeling of the device structure and with large area
spin Seebeck measurements.
