X-ray magnetic circular dichroism characterization of GaN∕Ga1−xMnxN digital ferromagnetic heterostructure

Abstract

We have investigated the magnetic properties of a GaN/Ga 1−x Mn x N (x = 0.1) digital ferromagnetic heterostructure (DFH) showing ferromagnetic behavior using soft x-ray absorption spectroscopy (XAS) and x-ray magnetic circular dichroism (XMCD). The Mn L 2,3 -edge XAS spectra were similar to those of Ga 1−x Mn x N random alloy thin films, indicating a substitutional doping of high concentration Mn into GaN. From the XMCD measurements, it was revealed that paramagnetic and ferromagnetic Mn atoms coexisted in the Ga 1−x Mn x N digital layers. The ferromagnetic moment per Mn atom estimated from XMCD agreed well with that estimated from SQUID measurements. From these results, we conclude that the ferromagnetic behavior of the GaN/Ga 1−x Mn x N DFH sample arises only from substitutional Mn 2+ ions in the Ga 1−x Mn x N digital layers and not from ferromagnetic precipitates. Subtle differences were also found from the XMCD spectra between the electronic states of the ferromagnetic and paramagnetic Mn 2+ ions.

Effects of growth temperature on the valence, optical and magnetic properties of Mn-doped GaN films grown by metal organic chemical vapor deposition

“…The spectra of film C are close to the typical calculated spectra of Mn 3+ in Ref. [18] and are attributed to Mn 3+ or hybridized Mn d 4 -d 5 -d 6 by the authors [25,26]. In the present work, the spectra of film C can be tentatively assigned to Mn 3+ ions, and the different spectrum structure of film C is originated from different 10Dq and hybridization in film C with comparison to that of film A.…”

Element-specific field-induced spin reorientation and an unusual tetracritical point in MnCr2S4

“…Figure 1 shows zero-field X-ray absorption spectroscopy (XAS) and XMCD results at the Mn and Cr L 3 edge measured at 15 K. In order to prepare a single-magnetic domain, a pulsed field of up to 20 T along the [110] axis (hereafter called initial field) was applied before taking the zero-field spectra. The XAS spectra with multiplet structures agree with those previously reported for Mn 2+ in tetrahedral [21] and Cr 3+ in octahedral symmetry [22,23]. Note that the Mn XAS and XMCD give an average information on the two nonequivalent Mn sublattices.…”

Digital magnetic heterostructures based on GaN using GGA-1/2 approach

“…9 DMH has already been achieved experimentally for GaAs d-doped with Mn, leading to T c ¼ 250 K. 10 Another good example is GaMnN monolayers (MLs) embedded in GaN: this d-doping technique permits not only to synthesize GaMnN ML with a Mn composition much higher than the one achievable with bulk-GaMnN, but also to enhance the magnetization and the T c of the sample. [11][12][13] A DMH has also been proposed for Si, to overcome the difficulty of Mndoping.…”