2007 Fiscal Year Final Research Report Summary
Pressure effect on phonon physics and slow dynamics of Griffith phase in bilayered manganese oxides
| Project/Area Number |
18540333
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Condensed matter physics II
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| Research Institution | Iwate University |
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Principal Investigator |
MITSUKAWA Michiaki Iwate University, Faculty of Engineering, Professor (40221585)
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| Co-Investigator(Kenkyū-buntansha) |
YOSHIMOTO Noriyuki Graduate school of Engineering, 工学研究科, Associate Professor (80250637)
NAKANISHI Yoshiki Graduate school of Engineering, 工学研究科, Assistant Professor (70322964)
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| Project Period (FY) |
2006 – 2007
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| Keywords | bilayered manganite / colossal magnetoresistive effect / magnetostriction / pressure effect / orbital frustration / lattice transformation |
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| Research Abstract |
We have studied the pressure effect on magnetostriction, both in the ab plane and along the c axis of a (La,Pr)_<1.2>Sr_<1.8>Mn_2O_7 bilayered manganite single crystal over the temperature region where the field-induced ferromagnetic metal_FMM_transition takes place. For comparison, we have also examined the pressure dependence of magnetization curves at the corresponding temperatures. The applied pressure reduces the critical field of the FMM transition and it enhances the remanent magnetostriction. An anomalous pressure effect on the remanent lattice relaxation is observed and is similar to the pressure effect on the remanent magnetization along the c axis. These findings are understood from the viewpoint that the double-exchange interaction-driven FMM state is strengthened by the application of pressure.
Next, we have reported a steplike lattice transformation of single crystalline (La_<0.4>Pr_<0.6>)_<1.2>Sr_<1.8>Mn_2O_7 bilayered manganite accompanied by both magnetization and magnetoresistive jumps, and examine the ultrasharp nature of the field-induced first-order transition from a paramagnetic insulator to a ferromagnetic metal phase accompanied by a huge decrease in resistance. Our findings support that the abrupt magnetostriction is closely related to an orbital frustration existing in the inhomogeneous paramagnetic insulating phase rather than a martensitic scenario between competing two phases.
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[Journal Article] Anomalous pressure effect on the remanent lattice striction of a (La,Pr)_<1.2>Sr_<1.8>Mn_2O_7 bilayered manganite single crystal2007
Author(s)
M. Matsukawa, A. Tamura, S. Nimori, R. Suryanarayanan, T. Kumagai, Y. Nakanishi, M. Apostu, A. Revcolevschi, K. Koyama, N. Kobayashi
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Journal Title
PHYSICAL REVIEW B VOL. 75
Pages: 014427-1-6
Description
「研究成果報告書概要(欧文)」より
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