Pressure and field tuning in the Kondo lattice ferromagnet CeAgSb2

The intermetallic compound CeAgSb2 is an unusual example of a ferromagnetically ordered Kondo lattice system. Ferromagnetism sets in below the Curie temperature TC = 9.6 K at ambient pressure and zero fields. We have investigated the sensitivity of the ferromagnetic phase to hydrostatic pressure and a transverse magnetic tuning field using a series of resistivity and magnetization measurements. With pressure, TC is suppressed rapidly, and extrapolates to zero at 35 kbar. The ferromagnetism arising in CeAgSb2 is uniaxial, with the ordered moment aligning along the tetragonal c‐axis. The application of an in‐plane tuning field similarly suppresses TC, and drives the transition to zero temperature by 2.8 T. The character of the phase transition remains continuous on the approach to T = 0 K, and it is found that the quadratic A coefficient from the resistivity is strongly enhanced near the critical field.