Structural, electronic, and magnetic properties of double perovskite Pb2CrMO6 (M=Mo, W and Re) from first-principles investigation

• Our first-principles calculation show that a magnetic I4/m structure is lowest in total energy per formula unit for Pb2CrMO6 (M=Mo, W, and Re).
• With spin–orbit coupling included, the spin polarization of Pb2CrMO6 at the Fermi level remains 90%–99%.
• The simulated Curie temperature (Tc) values by Monte Carlo method are at least 480 K, which is favorable for potential spintronic applications.

We use first-principles methods to study double perovskite Pb2CrMO6 (M: some 4d and 5d transition metals), and find that a magnetic I4/mI4/m structure is lowest in total energy per formula unit for M=Mo, W, and Re. Our electronic structure investigation shows that the three double perovskite compounds are half-metallic ferrimagnets with total magnetic moments of 2μB2μB, 2μB2μB and 1μB1μB per formula unit, respectively. With the spin–orbit coupling included, our calculations show the high magnetocrystalline anisotropy (MCA) in Pb2CrReO6. Fortunately, the spin polarization of Pb2CrMO6 at the Fermi level remains 90% ~99%~99%. The orbital moments of 3d Cr and 4d Mo are small, but the 5d ions of W and Re have large unquenched orbital moments, which can be attributed stronger spin–orbit coupling in the 5d orbitals than in 3d/4d ones. In addition, these results are confirmed by using improved exchange–correlation functionals. Furthermore, we calculate the spin exchange constants of the three Pb2CrMO6, and our Monte Carlo simulated Curie temperatures for them are at least 480 K. These materials, when synthesized, should be useful in spintronics.