Magnetic frustration effect in Mn-rich Sr 2 Mn 1 − x Fe x MoO 6 system

Variation in lattice parameters and magnetic properties of Sr 2 Mn 1 − x Fe x MoO 6 ( 0 ≤ x ≤ 0.4 ) has been studied in the present work. Our findings suggest that the crystal structures at room temperature for all the compositions studied here are pseudocubic in nature. Substitution of as small as 10% Fe in place of Mn destroys the long range antiferromagnetic ordering observed in Sr 2 MnMoO 6 and introduces local magnetic frustration, i.e., short range ferromagnetic interactions centered around the substituted Fe atoms, although the shape of the magnetic susceptibility creates an illusion of antiferromagnetic ordering. Different local structural environments around Mn and Fe atoms are thought to be responsible for the presence of such magnetic frustration. The results have been compared with those observed previously in SrLaMnMoO 6 . Our detailed measurements and interpretations are clearly at variance with the magnetic phase diagrams of Mn-rich phases of Sr 2 Mn 1 − x Fe x MoO 6 compounds reported earlier, although the experimental results appear to be similar in both cases.