High Field Ferromagnetic Resonance Spectrometer: Magnetic Thin Film Measurement System

Ferromagnetic resonance is an intrinsic property of magnetic materials. Under microwave irradiation, magnetic moments in magnetic materials will precess around the effective magnetic field direction that is the sum of the applied magnetic field, magnetic anisotropic fields, demagnetizing field, and microwave magnetic field. A ferromagnetic resonance spectrometer measures the ferromagnetic resonance spectroscopy, which determines the saturation magnetization Ms, gyromagnetic ratio γ, damping constant (or Gilbert damping constant), magnetic anisotropy constants and their symmetry with respect to magnetic thin film. It should be emphasized that ferromagnetic resonance spectroscopy is the only method to accurately determine the saturation magnetization without the needs of determining sample weight or volume.  

Ferromagnetic resonance spectrometer 1

The Spectrum Magnetics Ferromagnetic Resonance Spectrometer Magnetic Thin Film Measurement System (FMR-THMS) is a fully automated, computer driven system for measurement of ferromagnetic resonance spectra of magnetic thin film samples at frequencies up to 50GHz and magnetic fields up to 2.0T.  The FMR-THMS uses a network analyzer for generating and detecting microwave signals, and can thus be extended to measure spin wave spectroscopy, magnetic permeability and dielectric permittivity spectra.

FMR-THMS Features:

  • Broadband ferromagnetic resonance measurements up to 50 GHz
  • DC magnetic field up to 2.0T
  • DC magnetic field accuracy: 0.075%
  • Signal sensitivity: 0.005 dB
  • In-plane and out-of-plane measurements with angle dependence
  • Background signal subtraction
  • Fully automated control and analysis software suite
  • Dual CPW Fixtures for easy transition between in-plane and out-of-plane measurements (No changing of cables or fixtures required)
  • 2.0 H-Frame electromagnet with full 360 degree powered rotation
  • 15kW power supply with polarity reversal unit

FMR-THMS Control & Analysis Suite

The FMR-THMS features a full suite of control and analysis software. The user-friendly software allows the user to create custom sweep profiles, easily switching between in-plane and out-of-plane measurements. The analysis software contains realtime data viewing, curve fitting, parameter extraction, and custom data exporting.

Ferromagnetic resonance parameters
Ferromagnetic resonance machine 2

Sample Data

The data below shows the measured response of a magnetic thin film with perpendicular anisotropy and the following structure Ta(2nm)/MgO/CoFeB(1nm)/Ta(0.4nm)/CoFeB(0.8nm)/MgO/Cap, measured in a perpendicular orientation at select frequencies.

Sample data graph 1
Sample data graph 2
Sample data graph 3