Ferromagnetic resonance of perpendicularly magnetized Tm3Fe5O12/Pt heterostructures

Broadband ferromagnetic resonance is used to investigate magnetization dynamics, damping, interfacial spin transport, and perpendicular magnetic anisotropy (PMA) of (111)-oriented epitaxial thin films of the ferrimagnetic insulator Tm3Fe5O12 (TmIG) on substrates of (111)-oriented Gd3Ga5O12. A PMA field of similar to 162 mT is found at 350 K, in the temperature range where spin-orbit torque switching was previously reported [Avci et al., Nat. Mater. 16, 309-314 (2017)]. A Lande g-factor of 1.56 strongly supports large intrinsic spin-orbit coupling due to the presence of the heavy rare earth Tm. Gilbert damping coefficients alpha are compared for three samples: a 28 nm thin TmIG film (alpha similar to 0.014), a TmIG (28 nm)/Pt (6 nm) bilayer (alpha similar to 0.022), and a TmIG (28 nm)/Cu (3 nm)/Pt (6 nm) trilayer (alpha similar to 0.024). Applying the spin pumping formalism, we find that the real part of the effective interfacial spin mixing conductance G(up down arrow)(eff) # = 5.7 x 10(14) Omega(-1) m(-2) is comparable to that of well-studied garnet/Pt interfaces. Our work strengthens the candidacy of TmIG for spintronics applications requiring PMA in insulating thin films. Published under license by AIP Publishing.