Skip to main content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.


The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Ferromagnetic Resonance Spectroscopy with a Micromechanical Calorimeter Sensor



John M. Moreland, M. Loehndorf, Pavel Kabos, Robert D. McMichael


We describe a new type of ferromagnetic resonance (FMR) spectroscopy that is based on a calorimeter sensor. We use an atomic force microscopy cantilever coated with a ferromagnetic thin film as a bimaterial sensor to measure absorption of microwaves at 9.17 GHz. The spectra show a peak in the cantilever deflection as a function of applied magnetic field corresponding to a peak in the absorbed microwave power that occurs at the FMR resonance of the ferromagnetic film. The saturation magnetization M3ff and the damping factor α were determined from the FMR microwave absorption spectra for Co, NiFe, and Ni thin films. The data correlate well with conventional FMR spectra taken with a tuned cavity spectrometer. Our instrument can detect magnetic moments as small as 1.3 c 10-12 A m2 (1.3X10-9 emu) with prospects for snesitivity improvements to the 1 x 10u-16^ Am2 (1X10-12emu) level. The technique provides a potentially superior way to make quantitative measurements of saturation magnetization of thin-film samples with very small total magnetic moments.
Review of Scientific Instruments


atomic force microscopy, bimetallic thermal sensor, ferromagnetic resonance, magnetic moments, thermal absorption, thin-film samples
Created August 1, 2000, Updated January 27, 2020