Antiferromagnetism of metastable Cr-rich Cr-Gd alloys

Abstract

Cr is an antiferromagnet with a Néel temperature of 311 K. The addition of impurities will alter the antiferromagnetic properties of materials. Studies of the effect of magnetic Gd atoms on the Cr-rich CrxGd1−x alloys are reported. The metastable CrxGd1−x alloy films (1.00≥x≥0.96) have been prepared by the rapid-quenching method. It has been found from x-ray diffraction that the alloy films with 1.00≥x≥0.97 have body-centered-cubic structure, the same as Cr. For higher Gd concentration, the alloy film contains both body-centered cubic and amorphous phases. The variation of the Néel temperature TN as well as the spin-flip temperature TF of metastable Cr-Gd alloys has been investigated by resistiviity measurements between 10 and 300 K. It has been found that TN decreases slowly from 311 K for pure Cr to about 290 K for Cr0.97Gd0.03. These results seem to indicate that magnetic Gd atoms show little effect on the antiferromagnetism of Cr. Furthermore, there is a broad resistivity minimum at low temperatures. This broad minimum occurs at higher temperature as Gd concentration is increasing. Thus, it suggests that a different mechanism accounts for this resistivity minimum. A detailed discussion is reported.