Abstract
For mobile communication, the ferromagnetic resonance frequency of magnetic films must be over 3 GHz. A suitable anisotropic field and high resistivity for high frequency applications were obtained by inserting insulator (AlO x ) layers into ferromagnetic layers (FeCoHfO). With this optimum configuration of three layers structure [FeCoHfO (400 nm)/AlO x (10 nm)] 3 , high frequency characteristics (permeability ∼ 100 at 100 MHz and ferromagnetic resonance frequency over 3 GHz) and high resistivity (ρ ∼ 1088) μΩ cm were achieved. © 2010 Elsevier Ltd. All rights reserved.