The Structural, Anisotropic Magnetization, and Spectroscopic Study of Delafossite CuCr1-x M x O2 Systems

This work describes the chemical doping effect on the magnetic properties of p-type transparent semiconductor with delafossitetype oxides CuCr (0.95) M (0.05) O (2) (M = Ni, Cr, Ga, V, Fe, Mn, and Zn). The lattice parameters were found to vary according to Vegard's law. Reflection broadening is observed, that is ascribed to local lattice distortion due to the ionic radius difference between Cr (3+) and M dopants Raman spectra at a room temperature of CuCr (0.95) M (0.05) O (2) displayed three intense modes which are identified as sigma(A (1g)) at 691 cm (-1), sigma(E (g)) at 444 cm (-1) and sigma(A (g)) at 207 cm (-1) that matched with other delafossite structures. Magnetic susceptibility measurements show that the dominant interactions are antiferromagnetic (AFM) but that doping induces significant changes. A large ferromagnetic component arises in the Fe, V and Mn-substituted samples below a parts per thousand 120 K. The Ni, Zn and Ga-substituted phases retain antiferromagnetic ordering at T (N)a parts per thousand 24 K. The main origin of the stabilization of the AFM state is probably the randomness induced by doping. The coupling between the local spins at the Cr sites and doped metal transition may enhance spin fluctuations at the Cr sites, which break the residual magnetic degeneracy as fluctuation-induced symmetry breaking in a highly magnetic degenerate groundstate manifold of some frustrated systems.