INFLUENCE OF VANADIUM ON SPIN-DENSITY AND CHARGE-DENSITY WAVES IN CHROMIUM

Sn-119 Mossbauer spectroscopy is applied to study the influence of van adium on spin- and charge-density waves in single-crystal and polycrys talline samples of chromium at 4.2 and 295 K. It has been found that V doping drastically quenches spin-density waves (SDW's). In single cry stals the amplitude of the SDW, which was assumed to be proportional t o the maximum hyperfine (hf) field, H-max and the average hf field, [H ] decrease linearly with the concentration (x) of V. The former at the rate of 26.2 kOe/at. % and the latter at 18.7 kOe/at. %. The normaliz ed decrease of both quantities, N = H-max or [H], was found to be the same, (dN/N)/dx=-0.3/at. %. It agrees well with the normalized decreas e of the Neel temperature, the average magnetic moment, and the incomm ensurability wave vector. This strongly supports the claim that the sp ectral parameters viz. H-max and [H] are directly related to the densi ty of electrons at the Fermi surface and further supports the canonica l model for SDW antiferromagnetism of chromium. Enhanced values of all spectral parameters characteristic of the SDW's and charge-density wa ves (CDW's), except the (H) values, have been determined in the polycr ystalline samples. The enhancement is in part due to the interactions of SDW's and CDW's with grain boundaries, and partly to the internal s train. Residual SDW's have been revealed to exist in these samples at 295 K.