Effect of B-site Dopants on Magnetic and Transport Properties of LaSrCoRuO6_6

Effect of Co, Ru and Cu substitution at B and B' sites on the magnetic and transport properties of LaSrCoRuO$_6$ have been investigated. All the doped compositions crystallize in the monoclinic structure in the space group $P2_1/n$ indicating a double perovskite structure. While the magnetization and conductivity increase in Co and Ru doped compounds, antiferromagnetism is seen to strengthen in the Cu doped samples. These results are explained on the basis of a competition between linear Co-O-Ru-O-Co and perpendicular Co-O-O-Co antiferromagnetic interactions and due to formation of Ru-O-Ru ferromagnetic networks

MAGNETIC PROPERTIES OF K2NiF4 TYPE OXIDES, SrLaMnO4+x (0 ≤ x ≤ 0.2)

Magnetization of SrLaMnO4+x (0 ≤ x ≤ 0.2) and neutron diffraction of stoichiometric SrLaMnO4 reveal that oxygen excess SrLaMnO4+x is ferromagnetic and stoichiometric SrLaMnO4 is an antiferromagnet with a wave vector [1/2, 1/2, 0] and TN = 180 K. In SrLaMnO4+x, ferromagnetic clusters are associated with coupling between Mn3+ and Mn4+ ions produced in antiferromagnetic SrLaMnO4