The sound velocity and attenuation are measured using a pulse-echo method with a phase-sensitive detection technique .
Principle sketch of the measurement setup
The ultrasound frequency is 5 - 500 MHz.
The sample size should be > 0.5 mm along the sound propagation.
Standard temperature range is 1.3 – 300 K. Low temperatures in a 3He-system are possible.
The technique is best suited for magnet types A or B but can be installed in all other magnets.
The resolution for the relative sound-velocity change is 10-5 and 10-3 for the sound attenuation.
Sound velocity versus magnetic field in the frustrated antiferromagnet CdCr2O4 .