Magnetoresistance peak in the vicinity of the charge disproportionation/ordering transition in the R1/3Sr2/3FeO3-δ (R=La, Pr) perovskite

V. P.S. Awana; J. Nakamura; J. Lindén; M. Karppinen; H. Yamauchi

doi:10.1016/S0038-1098(01)00228-9

Magnetoresistance peak in the vicinity of the charge disproportionation/ordering transition in the R_1/3Sr_2/3FeO_3-δ (R=La, Pr) perovskite

V. P.S. Awana
, J. Nakamura
, J. Lindén
, M. Karppinen
, H. Yamauchi^*

^*Corresponding author for this work

Physics

Research output: Contribution to journal › Article › Scientific › peer-review

8 Citations (Scopus)

Abstract

In this letter, we present evidence that charge disproportionation (CD) and/or charge ordering (CO) states have influence upon magnetotransport in both compounds, R_1/3Sr_2/3FeO_3-δ (R=La and Pr). Field-dependent resistivity versus temperature measurements reveal the existence of a magnetoresistance (MR) peak in the temperature regime where the CD/CO transition takes place. Further increased MR of up to 6.5% is observed at temperatures as low as 25 K. These compounds are basically semiconductors which below the CD/CO temperature follow the variable range hopping process down to around 50 K and at even lower temperatures again turn to moderately doped semiconductors. Magnetization measurements show that the CD/CO is accompanied by an antiferromagnetic spin ordering of Fe ions with a further weak ferromagnetic component at low temperatures. While an ordering of Fe(III) and Fe(V) species seems to cause the MR peak near the CD/CO temperature, the appearance of some ferromagnetic component within an antiferrognatically ordered state may be largely responsible for the MR at low temperatures.

Original language	English
Pages (from-to)	159-162
Number of pages	4
Journal	Solid State Communications
Volume	119
Issue number	3
DOIs	https://doi.org/10.1016/S0038-1098(01)00228-9
Publication status	Published - 17 Jul 2001
MoE publication type	A1 Journal article-refereed

Funding

Prof. Shunri Oda is gratefully acknowledged for allowing the authors to use his equipment in the magnetoresistance measurements. Ms Kirsi Salomäki is thanked for her help in cerimetric titrations. The present work has been supported by the Grant-in-Aid for Scientific Research (Grant No. 11305002) from the Ministry of Education, Science and Culture of Japan, by the International Collaborative Research Project Grant-2000 of Materials and Structures Laboratory, Tokyo Institute of Technology, and by the Academy of Finland (Decision No. 46039). Two of the authors, V.P.S.A. and J.L., acknowledge the Japanese Society for Promotion of Sciences for awarding them Foreigners Post Doctoral Fellowship with ID P-00128 and ID P-99704, respectively.

Keywords

A. Magnetically ordered materials
D. Phase transitions
D. Valence fluctuations

Access to Document

10.1016/S0038-1098(01)00228-9

Cite this

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title = "Magnetoresistance peak in the vicinity of the charge disproportionation/ordering transition in the R1/3Sr2/3FeO3-δ (R=La, Pr) perovskite",

abstract = "In this letter, we present evidence that charge disproportionation (CD) and/or charge ordering (CO) states have influence upon magnetotransport in both compounds, R1/3Sr2/3FeO3-δ (R=La and Pr). Field-dependent resistivity versus temperature measurements reveal the existence of a magnetoresistance (MR) peak in the temperature regime where the CD/CO transition takes place. Further increased MR of up to 6.5\% is observed at temperatures as low as 25 K. These compounds are basically semiconductors which below the CD/CO temperature follow the variable range hopping process down to around 50 K and at even lower temperatures again turn to moderately doped semiconductors. Magnetization measurements show that the CD/CO is accompanied by an antiferromagnetic spin ordering of Fe ions with a further weak ferromagnetic component at low temperatures. While an ordering of Fe(III) and Fe(V) species seems to cause the MR peak near the CD/CO temperature, the appearance of some ferromagnetic component within an antiferrognatically ordered state may be largely responsible for the MR at low temperatures.",

keywords = "A. Magnetically ordered materials, D. Phase transitions, D. Valence fluctuations",

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T1 - Magnetoresistance peak in the vicinity of the charge disproportionation/ordering transition in the R1/3Sr2/3FeO3-δ (R=La, Pr) perovskite

AU - Awana, V. P.S.

AU - Nakamura, J.

AU - Lindén, J.

AU - Karppinen, M.

AU - Yamauchi, H.

PY - 2001/7/17

Y1 - 2001/7/17

N2 - In this letter, we present evidence that charge disproportionation (CD) and/or charge ordering (CO) states have influence upon magnetotransport in both compounds, R1/3Sr2/3FeO3-δ (R=La and Pr). Field-dependent resistivity versus temperature measurements reveal the existence of a magnetoresistance (MR) peak in the temperature regime where the CD/CO transition takes place. Further increased MR of up to 6.5% is observed at temperatures as low as 25 K. These compounds are basically semiconductors which below the CD/CO temperature follow the variable range hopping process down to around 50 K and at even lower temperatures again turn to moderately doped semiconductors. Magnetization measurements show that the CD/CO is accompanied by an antiferromagnetic spin ordering of Fe ions with a further weak ferromagnetic component at low temperatures. While an ordering of Fe(III) and Fe(V) species seems to cause the MR peak near the CD/CO temperature, the appearance of some ferromagnetic component within an antiferrognatically ordered state may be largely responsible for the MR at low temperatures.

AB - In this letter, we present evidence that charge disproportionation (CD) and/or charge ordering (CO) states have influence upon magnetotransport in both compounds, R1/3Sr2/3FeO3-δ (R=La and Pr). Field-dependent resistivity versus temperature measurements reveal the existence of a magnetoresistance (MR) peak in the temperature regime where the CD/CO transition takes place. Further increased MR of up to 6.5% is observed at temperatures as low as 25 K. These compounds are basically semiconductors which below the CD/CO temperature follow the variable range hopping process down to around 50 K and at even lower temperatures again turn to moderately doped semiconductors. Magnetization measurements show that the CD/CO is accompanied by an antiferromagnetic spin ordering of Fe ions with a further weak ferromagnetic component at low temperatures. While an ordering of Fe(III) and Fe(V) species seems to cause the MR peak near the CD/CO temperature, the appearance of some ferromagnetic component within an antiferrognatically ordered state may be largely responsible for the MR at low temperatures.

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KW - D. Valence fluctuations

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