Logo
ScienceStack
Table of Contents
Fetching ...
Sign In

Linear and isotropic magnetoresistance of Co$_{1-x}$Fe$_x$Si at x=0.2; 0.4; 0.65

A. E. Petrova, S. Yu. Gavrilkin, V. A. Stepanov, S. S. Khasanov, Dirk Mensel, S. M. Stishov

TL;DR

This study investigates magnetoresistance in Co$_{1-x}$Fe$_x$Si with $x=0.2$, $0.4$, and $0.65$ across $T=1.8$–$100$ K under fields up to $9$ T, focusing on two magnetic-field orientations relative to the current. Both transverse and longitudinal MR exhibit quasilinear dependence on the field at low temperatures, while MR becomes conventional with a power-law exponent near $2$ at higher temperatures; MR is found to be nearly isotropic at $1.8$ K for all compositions, though isotropy weakens for $x=0.2$ at higher $T$. The authors attribute the linear MR and MR isotropy to a combination of Weyl-band topology and disorder-induced current-path distortions, with spin polarization potentially enhancing MR in magnetically ordered samples. The results imply a complex interplay between Weyl physics and disorder in these Co-Fe-Si B20 compounds, suggesting further experimental and theoretical work to delineate the roles of topology, magnetism, and inhomogeneity.

Abstract

We studied the magnetoresistance (MR) of well-characterized samples of Co$_{1-x}$Fe$_x$Si at x=0.2, 0.4, and 0.65 at temperatures between 1.8 and 100~K and magnetic fields of 9~T. The quasilinear dependence of MR on the magnetic field at low temperatures and the practically isotropic properties of MR in these compounds are tentatively attributed to the specifics of Weyl electron spectra and general disorder of the materials.

Linear and isotropic magnetoresistance of Co$_{1-x}$Fe$_x$Si at x=0.2; 0.4; 0.65

TL;DR

This study investigates magnetoresistance in CoFeSi with , , and across – K under fields up to T, focusing on two magnetic-field orientations relative to the current. Both transverse and longitudinal MR exhibit quasilinear dependence on the field at low temperatures, while MR becomes conventional with a power-law exponent near at higher temperatures; MR is found to be nearly isotropic at K for all compositions, though isotropy weakens for at higher . The authors attribute the linear MR and MR isotropy to a combination of Weyl-band topology and disorder-induced current-path distortions, with spin polarization potentially enhancing MR in magnetically ordered samples. The results imply a complex interplay between Weyl physics and disorder in these Co-Fe-Si B20 compounds, suggesting further experimental and theoretical work to delineate the roles of topology, magnetism, and inhomogeneity.

Abstract

We studied the magnetoresistance (MR) of well-characterized samples of CoFeSi at x=0.2, 0.4, and 0.65 at temperatures between 1.8 and 100~K and magnetic fields of 9~T. The quasilinear dependence of MR on the magnetic field at low temperatures and the practically isotropic properties of MR in these compounds are tentatively attributed to the specifics of Weyl electron spectra and general disorder of the materials.

Paper Structure

This paper contains 7 sections, 10 figures.

Table of Contents

  1. Introduction
  2. Experimental
  3. Experimental results
  4. Discussion
  5. Conclusion
  6. acknowledgment
  7. Appendix

Figures (10)

  • Figure 1: Chiral crystal structure of binary compounds B20.
  • Figure 2: Band structure of FeSi, and CoSi with a B20 (P2$_1$3) crystal structure. Energy is measured relative to the fourfold intersection of the bands at point $\Gamma$. Dashed-dotted line shows position of the Fermi level Psh.
  • Figure 3: Band structure of CoSi near $E_F$ along high-symmetry directions of the Brillouin zone calculated Psh without taking into account spin-orbit interaction Tak.
  • Figure 4: Magnetoresistance of the parent compounds CoSi (a) Pet and FeSi (b) Pet2. Note nontrivial behavior of MR in semiconductive FeSi.
  • Figure 5: Longitudinal and transverse magnetoresistance of Co$_{1-x}$ Fe$_{x}$Si as functions of magnetic field and temperature.
  • ...and 5 more figures