Effect of La(0.67)Sr(0.33)MnO(3) electrodes on organic spin valves

Sayani Majumdar, H. Huhtinen, H. S. Majumdar, R. Laiho, R. Osterbacka

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Abstract

We report the effect of La0.7Sr0.3MnO3 (LSMO) electrodes on the temperature dependence of the magnetoresistance (MR) of LSMO/polymer/cobalt spin valves (SVs). LSMO films have been prepared by pulsed laser deposition on three different single crystal substrates using different deposition parameters. The films were characterized for their surface morphologies, structural, magnetic, and magnetotransport properties. Low deposition rate is found to be detrimental for growth of good quality films and polycrystalline films with grain boundary effects are observed in thicker films. The films on MGO (100) substrate show a broad paramagnetic to ferromagnetic transition, accompanied with a metal-insulator transition below room temperature. This indicates growth of some strained structures due to large lattice mismatch (9%) between the substrate and the film and presence of polycrystalline grain boundaries. The deposited films on STO (100) and NGO (001) show much sharper magnetic transition and metallic behavior indicating higher spin polarization (SP) of LSMO on these substrates at room temperature. SVs made on STO (100) show improvement in switching behavior and better MR response compared to the devices made on MGO (100) at low temperatures. No difference in MR response was found at room temperature in either case. We conclude that the bulk spin polarization of LSMO films is not very important in the SV operation. The loss of most of the SP carriers at the LSMO/organic semiconductor interface at room temperature is a more dominant effect and drastically reduces the MR signal.
Original languageEnglish
Article number033910
Pages (from-to)033910
JournalJournal of Applied Physics
Volume104
DOIs
Publication statusPublished - 2008
MoE publication typeA1 Journal article-refereed

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electrodes
room temperature
polarization
grain boundaries
organic semiconductors
pulsed laser deposition
thick films
cobalt
transition temperature
insulators
magnetic properties
temperature dependence
single crystals
polymers
metals

Cite this

Majumdar, Sayani ; Huhtinen, H. ; Majumdar, H. S. ; Laiho, R. ; Osterbacka, R. / Effect of La(0.67)Sr(0.33)MnO(3) electrodes on organic spin valves. In: Journal of Applied Physics. 2008 ; Vol. 104. pp. 033910 .
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abstract = "We report the effect of La0.7Sr0.3MnO3 (LSMO) electrodes on the temperature dependence of the magnetoresistance (MR) of LSMO/polymer/cobalt spin valves (SVs). LSMO films have been prepared by pulsed laser deposition on three different single crystal substrates using different deposition parameters. The films were characterized for their surface morphologies, structural, magnetic, and magnetotransport properties. Low deposition rate is found to be detrimental for growth of good quality films and polycrystalline films with grain boundary effects are observed in thicker films. The films on MGO (100) substrate show a broad paramagnetic to ferromagnetic transition, accompanied with a metal-insulator transition below room temperature. This indicates growth of some strained structures due to large lattice mismatch (9{\%}) between the substrate and the film and presence of polycrystalline grain boundaries. The deposited films on STO (100) and NGO (001) show much sharper magnetic transition and metallic behavior indicating higher spin polarization (SP) of LSMO on these substrates at room temperature. SVs made on STO (100) show improvement in switching behavior and better MR response compared to the devices made on MGO (100) at low temperatures. No difference in MR response was found at room temperature in either case. We conclude that the bulk spin polarization of LSMO films is not very important in the SV operation. The loss of most of the SP carriers at the LSMO/organic semiconductor interface at room temperature is a more dominant effect and drastically reduces the MR signal.",
author = "Sayani Majumdar and H. Huhtinen and Majumdar, {H. S.} and R. Laiho and R. Osterbacka",
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Effect of La(0.67)Sr(0.33)MnO(3) electrodes on organic spin valves. / Majumdar, Sayani; Huhtinen, H.; Majumdar, H. S.; Laiho, R.; Osterbacka, R.

In: Journal of Applied Physics, Vol. 104, 033910, 2008, p. 033910 .

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Effect of La(0.67)Sr(0.33)MnO(3) electrodes on organic spin valves

AU - Majumdar, Sayani

AU - Huhtinen, H.

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AU - Laiho, R.

AU - Osterbacka, R.

PY - 2008

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N2 - We report the effect of La0.7Sr0.3MnO3 (LSMO) electrodes on the temperature dependence of the magnetoresistance (MR) of LSMO/polymer/cobalt spin valves (SVs). LSMO films have been prepared by pulsed laser deposition on three different single crystal substrates using different deposition parameters. The films were characterized for their surface morphologies, structural, magnetic, and magnetotransport properties. Low deposition rate is found to be detrimental for growth of good quality films and polycrystalline films with grain boundary effects are observed in thicker films. The films on MGO (100) substrate show a broad paramagnetic to ferromagnetic transition, accompanied with a metal-insulator transition below room temperature. This indicates growth of some strained structures due to large lattice mismatch (9%) between the substrate and the film and presence of polycrystalline grain boundaries. The deposited films on STO (100) and NGO (001) show much sharper magnetic transition and metallic behavior indicating higher spin polarization (SP) of LSMO on these substrates at room temperature. SVs made on STO (100) show improvement in switching behavior and better MR response compared to the devices made on MGO (100) at low temperatures. No difference in MR response was found at room temperature in either case. We conclude that the bulk spin polarization of LSMO films is not very important in the SV operation. The loss of most of the SP carriers at the LSMO/organic semiconductor interface at room temperature is a more dominant effect and drastically reduces the MR signal.

AB - We report the effect of La0.7Sr0.3MnO3 (LSMO) electrodes on the temperature dependence of the magnetoresistance (MR) of LSMO/polymer/cobalt spin valves (SVs). LSMO films have been prepared by pulsed laser deposition on three different single crystal substrates using different deposition parameters. The films were characterized for their surface morphologies, structural, magnetic, and magnetotransport properties. Low deposition rate is found to be detrimental for growth of good quality films and polycrystalline films with grain boundary effects are observed in thicker films. The films on MGO (100) substrate show a broad paramagnetic to ferromagnetic transition, accompanied with a metal-insulator transition below room temperature. This indicates growth of some strained structures due to large lattice mismatch (9%) between the substrate and the film and presence of polycrystalline grain boundaries. The deposited films on STO (100) and NGO (001) show much sharper magnetic transition and metallic behavior indicating higher spin polarization (SP) of LSMO on these substrates at room temperature. SVs made on STO (100) show improvement in switching behavior and better MR response compared to the devices made on MGO (100) at low temperatures. No difference in MR response was found at room temperature in either case. We conclude that the bulk spin polarization of LSMO films is not very important in the SV operation. The loss of most of the SP carriers at the LSMO/organic semiconductor interface at room temperature is a more dominant effect and drastically reduces the MR signal.

U2 - 10.1063/1.2963814

DO - 10.1063/1.2963814

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