Microwave, magnetic, and structural properties of nanocrystalline exchange-coupled Ni 11 Co 11 Fe 66 Zr 7 B 4 Cu 1 films for high frequency applications

Nanocrystalline structured films of the alloy Ni 11 Co 11 Fe 66 Zr 7 B 4 Cu 1 were deposited by pulsed laser ablation deposition onto fused quartz substrates. A substrate temperature of 300 ° C was found to produce films consisting of body-centered-cubic (bcc) metallic grains suspended in an amorphous matrix. The bcc grain size ranged from 5 - 8 nm for substrate temperatures up to 300 ° C . Measured values of coercivity were consistently below 4 Oe for films having a saturation magnetization, as 4 π M S , of ∼ 16 kG with in-plane uniaxial anisotropy fields of 25 to 30 Oe . The ferromagnetic resonance peak-to-peak derivative linewidth was measured to be 34 Oe at a frequency of 9.61 GHz . The zero magnetic field ferromagnetic resonance occurred at ∼ 2 GHz . These films exhibit soft magnetic properties, high saturation induction, low microwave loss, and the structural stability desirable for thin film inductor applications.