https://doi.org/10.1140/epjb/e2011-20647-2
Regular Article
Magnetic properties of the ordered and disordered double perovskite Sr2Fe1+xMo1−xO6 (−1 ≤ x ≤ 1/3)
1
Institut Néel, CNRS and Université Joseph Fourier -
BP 166, 38042
Grenoble Cedex 9,
France
2
Instituto de Investigaciones en Materiales, Universidad Nacional
Autónoma de México - Apartado
Postal 70-360, 04510
México D. F.,
México
3
Centro de Investigación en Materiales Avanzados, S. C., Miguel de
Cervantes 120, Complejo Industrial Chihuahua, 31109
Chihuahua Chih.,
México
a e-mail: jaimeunam@gmail.com
Received:
7
August
2011
Received in final form:
27
September
2011
Published online:
3
November
2011
We have studied the effect of cationic disorder on the spin polarization of the double perovskite system Sr2Fe1+xMo1−xO6 with −1 ≤ x ≤ 1/3. The composition x = 0 corresponds to the well-known double-perovskite Sr2FeMoO6, which is expected to have complete spin polarization, however all samples present some degree of Fe/Mo disorder which reduces the tunneling magnetoresistance in granular samples. We consider an electronic model within the renormalized perturbation expansion Green’s functions, consisting in a correlated electron picture with localized Fe-ions and itinerant electrons interacting with the local spins via a double-exchange type mechanism. Our results show the influence of disorder on the density of states and the ground-state properties, particularly on the spin polarization over the whole range of x.
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2011