Soft X-ray Absorption Magnetic Circular Dichroism Study of Ferromagnetic Superconductor UGe₂

Abstract

X-ray absorption magnetic circular dichroism (XMCD) at the U N 4,5 edges was measured for the ferromagnetic superconductor UGe 2 in the normal state. The orbital and spin magneic moments deduced from the sum rule analysis of the XMCD data indicate that the U atom in UGe 2 is considered to be closer to the trivalent state rather than the tetravalent state. The temperature dependence of the XMCD signal does not show any significant anomaly at T * ∼30 K, where the resistivity anomaly was observed at ambient pressure. The XMCD measurement at the U N 2,3 edge indicates that the U 6 d electrons have negligibly small magnetic contributions.