Abstract:The nature of magnetic and electronic structure in double perovskite structure A₂FeMoO₆ (A = Sr, a, Ca) was calculated using the local spin density approximation (LSDA) and the LSDA+U Coulomb interaction method of density functional theory. The result shows that Sr₂FeMoO₆ is magnetic metallic material, whereas Ba₂FeMoO₆ and Ca₂FeMoO₆ are half-metallic materials. Fe has great effect on the magnetic property of double perovskite structure A₂FeMoO₆ materials. Because of the orbit hybridization and polarization between the metal element and O element, the Mo element has magnetic properties. The static magnetic moment of double perovskite structure A₂FeMoO₆ materials, the value of the magnetic moment of these A₂FeMoO₆ for (A＝Ca, Sr, Ba) are 3.626 43μ_B, 2.678 64μ_B, 3.706 17μ_B, respectively. The magnetic moment of Fe element in the crystal cell are, 3.626 43μ_B, 2.678 64 μ_B, 3.706 17μ_B. And the energy of crystal cells are −28 540.561 907Ry, −24 268.037 272Ry, −44 106.187 179Ry. These values are in agreement with the experiment values.

Key words: double perovskite A₂FeMoO₆; full-potential linearized augmented plane wave; half-metal; local density approximation