Neutron Diffraction Study of Cr under High Pressure

Abstract

The spin density wave in pure Cr was studied by neutron diffraction under high pressures up to 6 kbar. The spin flip temperature T S F decreases linearly with an increase of pressure with a cofficient -5.8±0.2°K/kbar. The wave vector Q ' of the spin density wave in units of 2π/ a also decreases with an increase of pressure. Since the Néel temperature T N decreases with increasing pressure, data were analyez at constsnt reduced temperatures T / T N . The initial derivatives of the pressure dependence of Q ', \(\left(\frac{1}{Q'}\frac{dQ'}{dP}\right)_{0}\), are -2.08±0.15×0.15×10 -3 kbar -1 at T / T N =1.0 and -0.64±0.10×10 -3 kbar -1 at T / T N =0.3. The spontaneous magnetic moment µ decreases in proprtion to T N with an increase of pressure. These features are discussed in the light of Lomer's two band model.