Imaging Nano- and Micrometer-sized Magnetic Insulator Devices in the Presence of Spin-Torque

Recent results demonstrate that a giant spin-hall effect in Tantalum can produce large spin torques. We intend to employ this large spin torque to manipulate the magnetic moment in electrically insulating ferrimagnetic Lu$_{\mathrm{3}}$Fe$_{\mathrm{5}}$O$_{\mathrm{12}}$ (LuIG) and Y$_{\mathrm{3}}$Fe$_{\mathrm{5}}$O$_{\mathrm{12}}$ (YIG) devices. Using a scanning SQUID microscope, we can study the possibility of performing reversible switching between magnetic states of nano- and micrometer-sized iron garnet devices induced by current pulses applied to a Tantalum layer in contact with the devices by directly imaging the magnetic state of the device before and after a current pulse. Successful manipulation of magnetic insulators by electrical pulses can be a platform for magnetic memory devices and spintronics.