Influence of thermal processing on magnetotransport characteristics of NdSr{sub 2}Mn{sub 2}O{sub 7+δ}
Highlights: • The NdSr{sub 2}Mn{sub 2}O{sub 7+δ} compounds with different oxygen non-stoichiometry were prepared. • According to XRD analysis, all the oxides were completely single-phase. • The strong competition between different types of magnetic exchange interactions was revealed. • The samples demonstrate semiconducting behavior over the explored temperature range. • A large negative magnetoresistance effect for all the compounds below 200 K was observed. - Abstract: Background: Influence of oxygen non-stoichiometry on magnetic and electric properties of the compounds has not almost been studied yet. Aim: Synthesis of a number of the NdSr{sub 2}Mn{sub 2}O{sub 7+δ} samples subjected to various thermal processing in air atmosphere and investigation of their structure, oxygen non-stoichiometry, electrical and magnetic properties. Method: The compounds obtained have been characterized by using X-ray diffraction (XRD) analysis, a modified gravimetric method, vibrating sample magnetometry (VSM) and standard DC four-probe method. Results: It was established that additional firing of the samples at different temperatures leads to essential changes in the oxygen non-stoichiometry. The noticeable magnetoresistance (MR) effect is observed for all the compounds below 200 K and increases monotonically as the temperature decreases. The MR values for the compounds as a function of oxygen content vary nonlinearly. The largest MR value of 380% at the 5 K and magnetic field of 7 T was achieved for the sample with the oxygen non-stoichiometry of δ = 0.03. Conclusions: The results observed are discussed in the assumption of ferromagnetic cluster formation in the compounds.
- OSTI ID:
- 22475823
- Journal Information:
- Materials Research Bulletin, Journal Name: Materials Research Bulletin Vol. 67; ISSN MRBUAC; ISSN 0025-5408
- Country of Publication:
- United States
- Language:
- English
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