Survey of Temperature Dependence of the Damping Parameter in the Ferrimagnet Gd₃Fe₅O₁₂

Abstract

The damping parameter 𝛼 FM in ferrimagnets defined by following the conventional practice for ferromagnets is known to be strongly temperature dependent and diverge at the angular momentum compensation temperature, where the net angular momentum vanishes. However, recent theoretical and experimental developments suggest that the damping parameter can be defined in such a way, which we denote by 𝛼 FiM , that it is free of the diverging anomaly at the angular momentum compensation point and is little dependent on temperature. To further understand the temperature dependence of the damping parameter in ferrimagnets, we analyze several data sets from literature for gadolinium iron garnet (Gd3Fe5O12) by using the two different definitions of the damping parameter. Using two methods to estimate the individual sublattice magnetizations, which yield results consistent with each other, we found that in all the used data sets, the damping parameter 𝛼 FiM does not increase at the angular compensation temperature and shows no anomaly whereas the conventionally defined 𝛼 FM is strongly dependent on the temperature.

Current-Induced Magnetization Switching Across a Nearly Room-Temperature Compensation Point in an Insulating Compensated Ferrimagnet

“…Gd 3 Fe 5 O 12 (GdIG) is a compensated ferrimagnetic insulator with a high Curie temperature (∼550 K) . Long spin transmission length and excellent magnon propagation in GdIG, even though not observed previously, are naturally expected in view of its low magnetic damping and absence of Ohmic loss . More strikingly, magnetization compensation temperature of bulk GdIG is close to room temperature ( T comp ∼ 295 K). , The characteristics of GdIG make it a prominent platform for room-temperature, ultrafast, and low-dissipation magnonic applications.…”