Electronic structure and magnetic properties of the half-metallic ferrimagnetMn2VAlprobed by soft x-ray spectroscopies

Abstract

We have studied the electronic structure of ferrimagnetic Mn2VAl single crystals by means of soft X-ray absorption spectroscopy (XAS), X-ray absorption magnetic circular dichroism (XMCD) and resonant soft X-ray inelastic scattering (RIXS). We have successfully observed the XMCD signals for all the constitute elements. The Mn L2,3 XAS and XMCD spectra are reproduced by spectral simulations based on density-functional theory, indicating the itinerant character of the Mn 3d states. On the other hand, the V 3d electrons are rather localized since the ionic model can qualitatively explain the V L2,3 XAS and XMCD spectra. This picture is consistent with local dd excitations revealed by the V L3 RIXS.

Microstructures and Interface Magnetic Moments in Mn2VAl/Fe Layered Films Showing Exchange Bias

“…All the XAS spectra shown in Figure 5 exhibit two main lines without fine structures at the Mn L 3,2 -absorption edges. A spectral hump, which is expected to appear at approximately 645 eV for the ordered L2 1 phase of Mn 2 VAl [19,21,32], is missing in the present data. It is consistent with the small volume fraction of the ordered phases in the samples, as evidenced by the present TEM images and supported by the previous X-ray diffraction experiment [26,27].…”

“…The XMCD for Sample C is also caused by Factor II; however, the situation is different from that in Sample D. In Sample C, the clusters of the L2 1 and B2 phases are considered to exist because of the analogy of the TEM images for Sample A shown in Figure 4, owing to the same deposition temperature for the Mn 2 VAl layer. Although Sample C shows no net magnetization because of the possible antiferromagnetism [9,24,25], the Mn-moments aligned by H exhibit XMCD with peak-splitting around the L 3 -edge, which is similar to the fully-ordered Mn 2 VAl samples in previous studies [19,21,32]. For both cases of Samples C and D, no hysteresis is observed for the ESMHs shown in Figure 8, which implies that there is no spontaneous magnetization in the samples.…”

“…Based on the scenario above, the XMCD spectra of Sample A can be decomposed using the XMCD spectrum of the fully-ordered Mn VAl with the L2 phase and that of Sample B, which is summarized in Figure 10 : For the decomposition, an XMCD spectrum of a bulk Mn VAl measured at of 2 T in Ref. [ 32 ] was used to simulate all the spectra of Sample A measured at different . The spectrum was arbitrarily scaled to adjust the peak amplitude, and the scaling factor was the same for all three cases.…”

“…The spectrum of L2 -Mn VAl was obtained from the Ref. [ 32 ] with permission from American Phyical Society, 2018, in which a magnetic field of 2 T was applied for the measurement. The blue, green, and red spectra in panels ( a – c ), respectively, are the original data of Sample A shown in Figure 6 a.…”

Distinct impact of order degree on thermoelectric power factor of p-type full-Heusler Mn2VAl compounds

“…Our previous work revealed that a half-metallic full-Heusler Mn 2 VAl compound is a promising p-type TE material [17]. Compared with other full-Heusler compounds, the Mn 2 VAl compound has an advantage that it can be easily prepared by various methods such as arc-melting [17,[19][20][21], spark-plasmasintering (SPS) [17], induction-melting [22,23], and ultra-high-vacuum magnetron sputtering technique [24][25][26]. A disadvantage of the Mn 2 VAl compound is its low PF=2.7×10 −4 Wm −1 K −2 at 717 K [17], being inferior to an n-type half-metallic full-Heusler Co 2 MnSi compound (2.9×10 −3 Wm −1 K −2 at 550 K [16]).…”