%0 Journal Article
%A Pradheesh, R.
%A Nair, Harikrishnan
%A Sankaranarayanan, V.
%A Sethupat, K.
%T Large Magnetoresistance and Jahn Teller effect in Sr$_2$FeCoO$_6$
%J The European physical journal / B
%V 85
%@ 1434-6028
%C Berlin
%I Springer
%M FZJ-2013-00649
%P 260
%D 2012
%X Neutron diffraction measurement on the spin glass double perovskite Sr$_2$FeCoO$_6$ reveals site disorder as well as Co$^{3+}$ intermediate spin state. In addition, multiple valence states of Fe and Co are confirmed through M'{o}ssbauer and X-ray photoelectron spectroscopy. The structural disorder and multiple valence lead to competing ferromagnetic and antiferromagnetic interactions and subsequently to a spin glass state, which is reflected in the form of an additional $T$-linear contribution at low temperatures in specific heat. A clear evidence of Jahn-Teller distortion at the Co$^{3+}$-O$_6$ complex is observed and incorporating the physics of Jahn-Teller effect, the presence of localized magnetic moment is shown. A large, negative and anomalous magnetoresistance of $approx$ 63% at 14K in 12T applied field is observed for Sr$_2$FeCoO$_6$. The observed magnetoresistance could be explained by applying a semi-empirical fit consisting of a negative and a positive contribution and show that the negative magnetoresistance is due to spin scattering of carriers by localized magnetic moments in the spin glass phase.
%F PUB:(DE-HGF)16
%9 Journal Article
%U <Go to ISI:>//WOS:000308403500029
%R 10.1140/epjb/e2012-30264-2
%U https://juser.fz-juelich.de/record/129129