Magnetic and electronic properties of CePt2In7 in high magnetic fields

Orateur : Ilya SHEIKIN (LNCMI)

Antiferromagnetic heavy fermion CePt2In7 has recently come to prominence due the observation of a pressure-induced quantum critical point and associated with it superconductivity. However, most of the so far reported results were obtained on either polycrystals or single crystals contaminated with other phases. In my talk, I will present the results of zero-field neutron diffraction, as well as high field specific heat and de Haas-van Alphen (dHvA) investigation of high quality phase pure single crystals of CePt2In7. Our preliminary neutron diffraction measurements reveal a simple antiferromagnetic structure with a propagation vector (1/2, 1/2, 1/2) that develops below the Neel temperature of 5.5 K. The magnetic phase diagram based on specific heat measurements suggests that a field-induced quantum critical point is likely to occur slightly below 60 T for both principal orientations of the magnetic field. The observed angular dependence of the dHvA frequencies indicates that some of the Fermi surfaces are almost ideally two-dimensional. The comparison of the experimental results with band structure calculations suggests localized 4f electrons deep inside the antiferromagnetic phase. Surprisingly, the Fermi surfaces do not seem to change across the field-induced quantum critical point. Throughout my talk, I will discuss similarities and differences between CePt2In7 and the well-studied less two-dimension compound from the same family, CeRhIn5.

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