Contactless measurements of Shubnikov-de Haas oscillations in the magnetically ordered state of CeAgSb2 and SmAgSb2 single crystals

Shubnikov-de Haas oscillations were measured in single crystals of highly metallic antiferromagnetic SmAgSb2 and ferromagnetic CeAgSb2 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 similar or equal to 20 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.