Journal Article

FZJ-2013-00649

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Large Magnetoresistance and Jahn Teller effect in Sr$_2$FeCoO$_6$

Pradheesh, R. (Corresponding author) ; Nair, H.FZJ* ; Sankaranarayanan, V. ; Sethupat, K.

2012
Springer Berlin

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Please use a persistent id in citations: http://hdl.handle.net/2128/10241  doi:10.1140/epjb/e2012-30264-2

Abstract: 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.

Keyword(s): Basic research (1st) ; Others (1st) ; Information Technology and Functional Materials (1st) ; Condensed Matter Physics (2nd)

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Contributing Institute(s):

1. JARA-FIT (JARA-FIT)
2. Streumethoden (PGI-4)
3. Streumethoden (JCNS-2)
4. JCNS-FRM-II (JCNS (München) ; Jülich Centre for Neutron Science JCNS (München) ; JCNS-FRM-II)

Research Program(s):

1. 422 - Spin-based and quantum information (POF2-422) (POF2-422)
2. 424 - Exploratory materials and phenomena (POF2-424) (POF2-424)
3. 542 - Neutrons (POF2-542) (POF2-542)
4. 544 - In-house Research with PNI (POF2-544) (POF2-544)
5. 54G - JCNS (POF2-54G24) (POF2-54G24)

Experiment(s):

1. Measurement at external facility

Appears in the scientific report 2012

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Database coverage:
; ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection ; Zoological Record

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