Steady-State and Pulse Measurement Techniques for Thin Magnetic Films in the vhf-uhf Range

Abstract

A vhf‐uhf bridge consisting of two loops placed symmetrically in a rectangular coaxial cavity has been used to study steady‐state and pulse relaxation in thin (∼1000 A) Permalloy films. For steady‐state measurements a coaxial transformer converts the bridge output from balanced‐to‐ground to unbalanced‐to‐ground; measurements from 100 to 1500 Mc are currently possible. Pulse measurements utilize the ungrounded deflection plates of a wide‐band traveling‐wave oscilloscope; pulse response to 2 mμsec can be resolved. Drive‐pulse calibration is accomplished unambiguously by using some of the unique switching properties of films which have uniaxial anisotropy.