TY  - JOUR
AU  - Pradheesh, R.
AU  - Nair, Harikrishnan
AU  - Sankaranarayanan, V.
AU  - Sethupat, K.
TI  - Large Magnetoresistance and Jahn Teller effect in Sr$_2$FeCoO$_6$
JO  - The European physical journal / B
VL  - 85
SN  - 1434-6028
CY  - Berlin
PB  - Springer
M1  - FZJ-2013-00649
SP  - 260
PY  - 2012
AB  - 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.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000308403500029
DO  - DOI:10.1140/epjb/e2012-30264-2
UR  - https://juser.fz-juelich.de/record/129129
ER  -