Magnetic phase diagram of the ferromagnetic Kondo-lattice compound CeAgSb2 up to 80 kbar -: art. no. 224419

Electrical resistivity and ac-calorimetric measurements reveal a complex magnetic phase diagram for single crystals of the ferromagnetic Kondo-lattice compound CeAgSb2 at high pressures up to 80 kbar. The ferromagnetic order at T-C=9.6 K at ambient pressure is completely suppressed at a critical pressure P-C=35 kbar. Another magnetic transition, possibly antiferromagnetic, found above 27 kbar, attains a maximum value T(N)similar to6 K at 44 kbar and then appears to be completely suppressed by similar to50 kbar. Thermodynamic and transport measurements in the ferromagnetic state indicate an energy gap Deltasimilar to30 K in the spin-wave excitation spectrum at ambient pressure which decreases to Deltasimilar to10 K at P=30 kbar. No superconductivity is observed at ambient pressure above Tsimilar to0.1 K, under applied pressure in the ferromagnetic state (P=28.5 kbar), nor in the antiferromagnetic state (P=33-46 kbar) above 0.3 K.