Elastic stability of magnetic crystals under isotropic compression and tension

Mechanical stability of Fe, Ni and Cr in their ground-state cubic structures has been tested under isotropic compressive and tensile loading using an analysis based on elastic moduli of the crystal system. This analysis has also been used to compute the theoretical strengths of the studied elements. Elasticity has been studied using small distortions from several reference cubic states and corresponding changes of crystal energy. The total energy has been computed by means of ab initio code that uses plane wave basis set. The exchange and correlation contribution to the total energy has been treated by means of generalized gradient approximation. Magnetic ordering has been taken into account via collinear spin polarization. No shear instability has been found in the region of tensile stresses up to the points of inflection on energy-volume dependencies of studied systems. (C) 2006 Elsevier B.V. All rights reserved.