Magnetic Structures of Field-Cooled and Stress-Cooled Chromium

Single crystals of chromium have been cooled through the Néel temperature in an applied magnetic field of 55 kG (field cooling) and with an applied compressive stress of 0.7 kg ${\mathrm{mm}}^{-2\mathrm{}}$ (stress cooling). The resulting magnetic structures of both states have been determined, by neutron diffraction, at temperatures of 78 and 294°K. The results are consistent with the assumption that field cooling favors the nucleation and growth of domains in which there exists a spin-density wave (SDW) with its vector parallel to the direction of the field applied during cooling; in stress cooling the development of domains with a SDW vector parallel to the direction of compressive stress is inhibited. Data on the anisotropy of magnetic susceptibility of field-cooled chromium suggest that the susceptibility of a SDW is maximum when measured normal to the direction of spin polarization. Data on the effect of field cooling on the anomalous temperature dependence of the resistivity of chromium near the Néel temperature are also discussed.