Pulsed laser deposited Y3Fe5O12 films: Nature of magnetic anisotropy I

Abstract

Recently we sintered by pulsed laser deposition (PLD) technique the epitaxial Fe-deficient yttrium iron garnet (YIG) films with ferromagnetic resonance (FMR) linewidth as narrow as 0.9 Oe, the uniaxial anisotropy as high as Hu=−880 Oe, and demonstrated them feasible for magnetostatic waves band pass filter application [Manuilov et al., J. Appl. Phys. 105, 033917 (2009)]. Here we explore the origin of unusually high noncubic magnetic anisotropy. Using the angular resolved FMR spectroscopy we found that in addition to strong uniaxial anisotropy, cubic magnetic anisotropy experienced almost fivefold reduction compared to standard YIG grown by liquid phase epitaxy. Molecular field theory was employed to calculate saturation magnetization 4πMs, cubic magnetocrystalline K1, and uniaxial anisotropy Ku in garnets with Fe vacancies. The modeling utilizes crystal field parameters that we revealed from earlier published experimental data on diamagnetic ion substituted Y3Fe5O12 and Fe-substituted isomorphous diamagnetic garnets. Consistent single ion anisotropy crystal field theory perfectly fits experimentally observed high saturation magnetization, reduction in cubic, and appearance of strong uniaxial anisotropy in PLD-grown Fe-deficient YIG films. The redistribution of Fe vacancies between different magnetic sublattices was quantified and confirmed that in YIG(111) films ferric ions preferentially leave vacant octahedrally coordinated sites. Simulation of growth induced anisotropy proves the ordering of Fe3+ vacancies within octahedral sites. At equal number of available ferric ions and vacancies, the latter populate the octahedrons with distortion axis perpendicular to the film surface with the probability equal to 0.67. Deformation blockage of octahedral complexes with distortion axes directed along the film surface reduces this probability down to 0.14.

Frequency and magnetic field mapping of magnetoelastic spin pumping in high overtone bulk acoustic wave resonator

“…The pattern shown in Fig. 2 [25][26][27] and that H ex (q cr ) ≈ δH, one can obtain exchange stiffness constant D ≈ 5×10 -9 cm 2 Oe typical for YIG and magnetization 4πM s ≈ 900 G typical for (La,Ga)YIG. The same measurements in the reversal field display that only the voltage sign change takes place.…”

Enhanced Magneto-optic Kerr Effect and Magnetic Properties ofCeY2Fe5O12Kehlberger1, Richter2, Onbaşlı3 et al. 2015Phys. Rev. Applied9010410View full textAdd to dashboardCite

“…f shape denotes the demagnetization term from the shape anisotropy, f cryst the contribution of the magnetocrystalline energy, which in the case of YIG should yield a cubic anisotropy [51], and f uni marks a uniaxial component, which can be induced by growth, stress, or interface effects in thin films. In general, pure YIG exhibits only a small magnetic anisotropy, which can be increased by a variation of the stoichiometry [52,53] or a growth-induced magnetoelastic contribution by selection of substrate lattice parameter [36].…”

Magnetic spheres in microwave cavities

“…In order to compare results with recent experiments, we chose parameters for YIG with gyromagnetic ratio γ /(2π ) = 28 GHz/T, saturation magnetization [41] μ 0 M s = 175 mT, Gilbert damping constant [15][16][17] …”