Hanle-effect measurements of spin injection from Mn₅Ge₃C_0.8/Al₂O₃-contacts into degenerately doped Ge channels on Si

Anomalous Hall effect in the noncollinear antiferromagnet Mn5Si3

“…21 Mn 5 Ge 3 and Mn 5 Ge 3 C x (x ≈ 1) have been proposed as ferromagnetic electrodes for spintronic applications due to their ability to grow epitaxially on Si and GaAs substrates. [22][23][24][25][26] In all these Mn compounds the different magnetic structures originate from the sensitivity of the Mn moment on the local atomic environment, in particular the Mn-Mn distances which are found to be the major factor leading to different site-dependent Mn moments. 27 Here, we report on measurements of the electrical resistivity and AHE of a Mn 5 Si 3 single crystal and polycystalline thin films.…”

Electrical detection of spin transport in Si two-dimensional electron gas systems

“…In the above process flow, the most critical step is the rapid thermal annealing that drives Mn to diffuse into the SiGe cap layer, in which the annealing temperature should be chosen carefully so as to form FM Mn(Si 0.7 Ge 0.3 ) x contact [28,29] but not to affect the doping profile of the Si/SiGe MODQW. Also, rather than using a Si (100) substrate, the (111) crystal orientation is chosen to improve the crystallinity of the formed Mn(Si 0.7 Ge 0.3 ) x upon annealing [18,30,31]. Previously we showed that the formed Mn 5 Ge 3 on a Si (111) substrate behaves like a ferromagnetic 'bad metal', whose conductivity is comparable to that of highly doped Ge; [31,32] accordingly, we do not expect a serious conductivity mismatch at the Mn(Si 0.7 Ge 0.3 ) x /Si interface (see online supplementary figure S4b).…”

“…Also, rather than using a Si (100) substrate, the (111) crystal orientation is chosen to improve the crystallinity of the formed Mn(Si 0.7 Ge 0.3 ) x upon annealing [18,30,31]. Previously we showed that the formed Mn 5 Ge 3 on a Si (111) substrate behaves like a ferromagnetic 'bad metal', whose conductivity is comparable to that of highly doped Ge; [31,32] accordingly, we do not expect a serious conductivity mismatch at the Mn(Si 0.7 Ge 0.3 ) x /Si interface (see online supplementary figure S4b). 3 ) x contacts for magneto-transport measurements.…”

Magnetic and Electrical Properties of Heusler Alloy Co2MnSi Thin Films Grown on Ge(001) Substrates via an Al2O3Tunnel Barrier

“…Moreover, in order to solve the lattice mismatch problem between the ferromagnetic metal and Ge channel, an insulator layer was always inserted between them [10][11][12]. In such kind of metal/insulator/semiconductor (M/I/SC) heterostructure, previous studies have reported that the magnitude of the observed spin signal was several orders larger than the magnitude from what is expected based on the available theory for spin injection and diffusion [12][13][14]; importantly, the spin signal varied with the thickness of the tunnel barrier [15,16]. At present, the physical mechanism for the anomalous scaling of the spin signal was still unclear.…”