Anomalous Anisotropic Magnetoresistance And Magnetization In Mn3.69Bi95.69Fe0.62

Abstract

It was found that the Mn3.69Bi95.69Fe0.62 consists of two phases, namely of a bismuth matrix and BiMn inclusions. It is shown that the samples have a crystalline texture. Independently on the applied field orientation, maximum on the temperature dependence of magnetization is detected at Tmax ≈ 85 K, which is associated with the reorientation transition of the magnetic moments of Mn for αBiMn phase. In turn, the electrical resistivity ρ(T) also demonstrates maximum at Tmax ≈58 K in a magnetic field of 800 kA/m when H⊥I. It is established that the maximum of ρ(T) increases and is shifted toward higher temperature Tmax≈94 K when field increasing up to 2400 kA/m. At the same time no clear maximum on ρ(T) is observed for H||I. It is shown that the relative magnetoresistance, Δρ/ρ0, is increased both with decreasing temperature and with increase of the magnetic field. The measured enhancement reaches Δρ/ρ0≈250% for H||I and Δρ/ρ0≈2400% for H⊥I in magnetic field of 2400 kA/m. Thus, the strong anisotropy of ρ(T) and Δρ/ρ0(T) is established both for H⊥I and H||I. Possible explanation of observed anomalous behavior of the temperature dependences of the electrical resistivity in magnetic fields has been proposed.

Keywords

• huge anisotropic magnetoresistance
• reorientation transition
• electron and hole Fermi surfaces
• MnBi alloys
• crystalline texture
• bismuth