Contact-less measurements of Shubnikov-de Haas oscillations in the   magnetically ordered state of CeAgSb$_2$ and SmAgSb$_2$ single crystals
  Shubnikov - de Haas oscillations were measured in single crystals of highly metallic antiferromagnetic SmAgSb$_{2}$ and ferromagnetic CeAgSb$_{2}$ using a tunnel diode resonator. Resistivity oscillations as a function of applied magnetic field were observed via measurements of skin depth variation. The effective resolution of $\Delta\rho\simeq20$ p$\Omega$ allows a detailed study of the SdH spectra as a function of temperature. The effects of the Sm long - range magnetic ordering as well as its electronic structure ($4f$-electrons) on the Fermi surface topology is discussed. 
Ruslan Prozorov, Matthew D. Vannette, German D. Samolyuk, Stephanie A.   Law, Sergey L. Bud'ko, Paul C. Canfield