If a magnetic field is applied to a magnetic material, the field produces a torque on the magnetization of the material and thereby drives the magnetization to precess. This precession is similar to the motion of a spinning top where the gravitational field produces a torque, instead of the magnetic field. It turns out that magnetization precession in yttrium iron garnet (Y3Fe5O12, YIG) decays slower than in any other known magnetic material. This fact gives rise to the recent birth of a new paradigm in the discipline of spintronics – "spintronics using yttrium iron garnets". This talk will touch on two issues related to YIG spintronics. The first part will present on the feasibility of the use of pulsed laser deposition (PLD) and magnetron sputtering to grow low-damping, nanometer-thick YIG films. It will be shown that the PLD YIG films in the 5-30 nm thickness range can have a Gilbert damping constant as low as 2.3×10-4, while the sputtered YIG films in the same thickness range can have an even lower damping constant (<10-4). The second part will report on spin-wave spin pumping using YIG thin films. It will be shown that there exist several different field/frequency regimes which present due to three-magnon splitting and show very different pumping efficiencies.
Department of Physics, Colorado State University, Fort Collins,