Spin- and orbital-moment compensation in the zero-moment ferromagnet Sm0.974Gd0.026Al2.

S.S. Dhesi (1, 2) , G. van Der Laan (1) , Peter Bencok (1, 2) , Nick B. Brookes (2) , Rose-Marie Galéra (3) , Philippe Ohresser (2, 4)

1 DIAMOND Light source
2 ESRF - European Synchrotron Radiation Facility
3 NEEL - MagSup - Magnétisme et Supraconductivité
4 SSOLEIL - Synchrotron SOLEIL

The balance between the orbital and spin magnetic moments of Sm3+ in the zero-moment ferromagnet Sm0.974Gd0.026Al2 has been studied using x-ray magnetic circular dichroism (XMCD) at the Sm M4,5 edges. The difference in the XMCD multiplet structure below and above the compensation point, Tcomp, demonstrates that the exchange and crystal-field interactions mix the low-lying 7=7/2 excited state into the Sm f5 6H5/2 ground state. Sum-rule analysis of the temperature-dependent XMCD reveals an anomalous change in the Sm3+ orbital to spin magnetic-moment ratio as the net magnetization vanishes at Tcomp. This behavior is ascribed to the role of the conduction electron-spin moment which couples parallel to the Sm spin moment.

Domaines: Electrons fortement corrélés [cond-mat.str-el]

S.S. Dhesi, G. van Der Laan, Peter Bencok, Nick B. Brookes, Rose-Marie Galéra, et al.. Spin- and orbital-moment compensation in the zero-moment ferromagnet Sm0.974Gd0.026Al2.. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 82, pp.180402-1. ⟨10.1103/PhysRevB.82.180402⟩. ⟨hal-00667313⟩