RAPID COMMUNICATION: Vector network analysis in swept-frequency microwave spectroscopy at low temperatures

Abstract

A microwave spectrometer is described that allows simultaneous detection of the real and imaginary part of the complex dynamic susceptibility with frequency f continuously varied between 0.3 and 10.7 GHz using vector analysis. Resonance or longitudinal susceptometry experiments can be carried out with the present set-up in the temperature range 2.5-300 K in magnetic fields up to 8*105 A m-1. Results of test measurements on ferromagnetic samples of EuS and LiTbF4 are presented.