Researchers from the National Institute of Standards and Technology (NIST) developed a new microscope, called a heterodyne magneto-optic microwave microscope (H-MOMM) that can measure the collective dynamics of elecrons spins. The microscope can measure the spin in individual magnets as small as 100 nanometers in diameter.
The NIST researchers used the H-MOMM to quantify, for the first time, the spin relaxation process—or damping—in individual nanomagnets. The results suggest that designing spintronic devices to have uniform spin waves could dramatically reduce the energy required to write a bit. They say that these results are "groundbreaking".
H-MOMM combines optical and microware technologies using two green laser beams. The beams are merged to generate microwaves, which excite “spin waves”—magnetic oscillations that vary with position across an individual nanomagnet. Polarized light from one laser is used to analyze the excitation pattern. By measuring excitation as a function of magnetic field and microwave frequency, researchers can deduce the damping of various spin waves in each nanomagnet.