Two Kinds of Cylindrical Fermi Surface Determined by de Haas–van Alphen Experiments in NpCoGa<sub>5</sub>

Dai Aoki, Yoshiya Homma, Yoshinobu Shiokawa, Etsuji Yamamoto, Akio Nakamura, Yoshinori Haga, Rikio Settai, Yoshichika Ōnuki

Journal of the Physical Society of Japan · 2004 · 47 citations · 10 references

Concepts

Abstract

We succeeded in observing de Haas–van Alphen (dHvA) oscillations in an antiferromagnet NpCoGa 5 with a tetragonal structure. The dHvA signal was significantly enhanced at higher fields than the metamagnetic transition field H m (=43 kOe for H ∥[001]), where the antiferromagnetic state is changed into the field-induced ferromagnetic (paramagnetic) state. In the paramagnetic state, the Fermi surface was found to consist of two kinds of cylindrical main Fermi surface and small pocket Fermi surfaces. The cyclotron masses of the main Fermi surfaces were considerably large, ranging from 6 to 12 m 0 . This is the first case where the Fermi surface was determined experimentally in transuranium compounds.

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