Mn K-edge XMCD in Mn₃ MC (M = Zn and Ga) perovskite

Abstract

Mn 3 MC (M=Zn and Ga) perovskite has attracted interest because of a variety of magnetic phase transitions. In this work, we measure temperature and magnetic field dependence of X-ray magnetic circular dichroism (XMCD) at Mn K-edge and discuss effect of second constituent metal on the magnetic states of Mn atoms.The spectrum in Mn 3 ZnC is characterized by a dispersion-type profile. In Mn 3 GaC, intensity of the positive peak at the edge is drastically reduced. The difference originates in charge transfer from Zn or Ga to Mn atoms. Temperature and magnetic field variations of the Mn K-edge XMCD spectrum suggest that orbital magnetic moments are closely related to the magnetic phase transition.

Ab initio calculation of X-ray magnetic circular dichroism spectra

“…Fig. 1 shows the XMCD spectra m c ðoÞ at the Mn K edge in Mn 3 GaC; in comparison with the experiment [6]. The XMCD spectra are in good agreement with the experiment; dips A, B, and peak C correspond well with the experimental ones A 0 ; B 0 ; and C 0 : The small peak at the Fermi level in the experiment is not reproduced in the calculation.…”

“…Fig. 2 shows the XMCD spectra m c ðoÞ at the K edge in Mn 3 ZnC; in comparison with the experiment [6]. The spectral shape is quite similar to that for Mn 3 ZnC; except for a large peak at the Fermi level (peak D).…”

“…XMCD spectra at the Mn K edge in Mn 3 GaC in comparison with the experiment[6]. The origin of energy corresponds to the excitation to the Fermi level.…”

“…Lower two panels show the spectra calculated with turning off the SOI on the p and d symmetric states at Mn sites, respectively. XMCD spectra at the Mn K edge in Mn 3 ZnC in comparison with the experiment[6].…”

“…They have a ferromagnetic phase above 168 K in Mn 3 GaC and above 233 K in Mn 3 ZnC [6]. We carry out the band calculation assuming a ferromagnetic phase with the magnetization fixed to the opposite of the ½1 1 1 direction, thereby neglecting small magnetic anisotropy.…”