Growth parameters of Bi0.1Y2.9Fe5O12 thin films for high frequency applications

TL;DR

This study investigates the growth, structural, and magnetic properties of Bi0.1Y2.9Fe5O12 thin films grown by pulsed laser deposition on different orientations, aiming to optimize them for high-frequency and magneto-optical applications.

Contribution

It provides detailed analysis of how substrate orientation and film thickness affect the structural and magnetic properties of Bi-YIG thin films, offering growth guidelines for high-frequency device use.

Findings

(111) oriented films show increased lattice constant and damping compared to (100) films.

Lowest Gilbert damping achieved is 1.06 x 10^-4 for (100) orientation at 150 nm thickness.

Four-fold symmetry observed in (100) films' in-plane magnetic anisotropy.

Abstract

The growth and characterization of Bismuth (Bi) substituted YIG (Bi-YIG, Bi0.1Y2.9Fe5O12) thin films are reported. Pulsed laser deposited (PLD) films with thicknesses ranging from 20 to 150 nm were grown on Gadolinium Gallium Garnet substrates. Two substrate orientations of (100) and (111) were considered. The enhanced distribution of Bi3+ ions at dodecahedral site along (111) is observed to lead to an increment in lattice constant from 12.379 angstrom in (100) to 12.415 angstrom in (111) oriented films. Atomic force microscopy images showed decreasing roughness with increasing film thickness. Compared to (100) grown films, (111) oriented films showed an increase in ferromagnetic resonance linewidth and consequent increase in Gilbert damping. The lowest Gilbert damping values are found to be (1.06) * 10E-4 for (100) and (2.30) * 10E-4 for (111) oriented films with thickness of 150 nm. The observed values of extrinsic linewidth, effective magnetization, and anisotropic field are related to thickness of the films and substrate orientation. In addition, the in-plane angular variation established four-fold symmetry for the (100) deposited films unlike the case of (111) deposited films. This study prescribes growth conditions for PLD grown single-crystalline Bi-YIG films towards desired high frequency and magneto-optical device applications.