The structure, Raman spectroscopy and evidence of ferromagnetic transition in CuCr1−xMxO2 (M=Mn and Rh) compounds

Abstract The CuCr 1− x M x O 2 (M=Mn, Rh) polycrystalline powders were synthesized by the direct solid state reaction of Cu 2 O and M 2 O 3 (M=trivalent cation or mixer of trivalent cation for transition metal). The magnetic susceptibility was measured in the temperature range of 0–300 K. It was found that the magnetic susceptibility ( χ ) increases rapidly with the doping of Cr 3+ by Mn 3+ and Rh 3+ ions with existence of paramagnetic substance at low temperature. With the substitution of magnetic Mn 3+ and Rh 3+ for Cr 3+ ( S =3/2), the antiferromagnetic (AF) transition becomes broader and the transition temperature increases. However, at low temperature, the magnetic data for CuCr 1− x M x O 2 (M=Mn, Rh) show evidence for weak ferromagnetic (FM) transition between 100 K and 130 K. Clear hysteresis loops indicate that FM order exists in both of them Mn or Rh-doped samples at 4 K. All samples behave like semiconductors. The ferromagnetism properties can be attributed to the double exchange interaction between the Mn 3+ or Rh 3+ and Cr 3+ semiconductors compounds.