Unexpected dependence of the anomalous Hall angle on the Hall conductivity in amorphous transition metal thin films

Abstract

Young women in sub-Saharan Africa are disproportionally affected by HIV infection and unintended pregnancies. However, hormonal contraceptive (HC) use may influence HIV risk through changes in genital tract microbiota and inflammatory cytokines. To investigate this, 130 HIV negative adolescent females aged 15-19 years were enrolled into a substudy of UChoose, an open-label randomized crossover study (NCT02404038), comparing acceptability and contraceptive product preference as a proxy for HIV prevention delivery methods. Participants were randomized to injectable norethisterone enanthate (Net-En), combined oral contraceptives (COC) or etonorgesterol/ethinyl estradiol combined contraceptive vaginal ring (CCVR) for 16 weeks, then crossed over to another HC for 16 weeks. Cervicovaginal samples were collected at baseline, crossover and exit for characterization of the microbiota and measurement of cytokine levels; primary endpoints were cervical T cell activation, vaginal microbial diversity and cytokine concentrations. Adolescents randomized to COCs had lower vaginal microbial diversity and relative abundance of HIV risk-associated taxa compared to Net-En or CCVR. Cervicovaginal inflammatory cytokine concentrations were significantly higher in adolescents randomized to CCVR compared to COC and Net-En. This suggests that COC use may induce an optimal vaginal ecosystem by decreasing bacterial diversity and inflammatory taxa, while CCVR use is associated with genital inflammation.

Large spin-orbit torque generated by amorphous iron silicide

“…Indeed, the Berry density shows welldefined functional dependence as a function of energy. Similar effects have been observed in amorphous CoFeB 50 and intrinsic contributions to AHE has been discussed [47][48][49] . This brings up an intriguing possibility -in a structure with a broken symmetry at the interface, an amorphous material should be able to generate spin current and potentially torque a magnet.…”

Amorphous Ferromagnetic Metal in van der Waals Materials

“…[ 17 ] Amorphous samples synthesized under different conditions can present different local atomic structures, although both lack a long‐range structural order. We also note that in amorphous ferromagnetic thin films such as CoFeB obtained by sputtering at room temperature, [ 27,28 ] the conductivity decreases naturally due to disorder, but M and $$\sigma _{xy}^A$$ are rather robust against disorder. Unlike previous studies on amorphous magnetic films, our CrGeTe 3 samples irradiated with heavy ions are more significantly affected by amorphization and exhibit totally different transport and magnetic properties from those of the crystalline phase.…”

Composition dependence of anomalous Nernst effect in amorphous TbFeCo thin films with perpendicular magnetic anisotropy

“…Karel et al discussed that increasing transition metal fraction leads the large anomalous Hall angle in amorphous systems. 20 The previous study also proposed introducing a rare-earth element or an element with large SOI to generate a larger nonzero Berry curvature in order to enhance anomalous Hall angle in amorphous systems. In this study, a TM-rich sample showed the large Hall angle tan θ H of about 5%.…”

“…Moreover, Berry curvature effects in amorphous magnetic materials have been discussed recently. [19][20][21] However, since the ANE is not large enough to use in practical application compared with the conventional Seebeck effect, further understanding of the ANE in magnetic materials is necessary to improve thermoelectric efficiency.…”