Adv. Search
Journal of Inorganic Materials

Journal of Inorganic Materials >

2007 , Vol. 22 >Issue 4: 715 - 719

DOI: https://doi.org/10.3724/SP.J.1077.2007.00715

Research Paper

Electrical Transport and Magnetoresistance in La0.67Ca0.33MnO3/MgO Composites

  • REN Guang-Ming ,
  • YUAN Song-Liu ,
  • MIAO Ju-Hong ,
  • YU Gong-Qi ,
  • XIAO Xun ,
  • YIN Shi-Yan
Expand
  • Department of Physics, Huazhong University of Science and Technology, Wuhan 430074, China

Received date: 2006-07-19

  Revised date: 2006-09-07

  Online published: 2007-07-20

Fold

Abstract

A La0.67Ca0.33MnO3(LCMO)/MgO granular composite system was fabricated by a chemical route. The grain size of the parent LCMO powders can be altered by controlling the initial sintering temperature. It shows that electrical transport and magetoresistive properties of the composite system strongly depend on the MgO content and initial sintering temperatures. For the samples with Ts1=1100℃, the insulator-metal transition can be observed only in pure LCMO and the x=1mol% composite. However, For the samples with Ts1=900℃, the insulator-metal transition can still be observed in the x=7mol% composite in which the maximal low field magnetoresistance (H=0.3T) is enhanced from 5% in pure LCMO to 27%. SEM analysis shows that
linking between LCMO grains is weakened with increasing MgO content or elevating the initial sintering temperature. The experimental results were discussed in terms of the spin polarized tunneling mechanism.

Key words： grain boundary effect; low field magnetoresistance; spin polarized tunneling; weak-link

Cite this article

REN Guang-Ming , YUAN Song-Liu , MIAO Ju-Hong , YU Gong-Qi , XIAO Xun , YIN Shi-Yan . Electrical Transport and Magnetoresistance in La0.67Ca0.33MnO3/MgO Composites[J]. Journal of Inorganic Materials, 2007 , 22(4) : 715 -719 . DOI: 10.3724/SP.J.1077.2007.00715

References

[1] 王克峰, 刘俊明. 物理学进展, 2003, 23 (2): 192--211.
[2] Jin S, et al. Science, 1994, 264: 413--415.
[3] 刘耀诚, 郭永权, 周和平, 等(LIU Yao-cheng, et al). 无机材料学报(Journal of Inorganic Materials), 1999, 14 (3): 475--478.
[4] Hwang H Y, et al. Phys. Rev. Lett., 1996, 77: 2041--2044.
[5] Yuan Song-Liu, Xia Zheng-Cai, et al. Chin. Phys. Lett., 2002, 19(8): 1168--1171.
[6] 袁松柳, 方重华, 缪菊红, 等(YUAN Song-liu, et at). 无机材料学报(Journal of Inorganic Materials), 2005, 20 (3): 623--628.
[7] Shilpi Karmakar, Taran S, Chaudhuri B K, et al. J. Phys. D: Appl. Phys., 2005, 38: 3757--3763.
[8] Huang Yun-Hui, Yan Chun-Hua, et al. Appl. Phys. Lett., 2002, 81: 76--78.
[9] Yuan Xiao-Bo, Liu Yi-Hua, Wang Cheng-Jian, et al. Appl. Phys. Lett., 2006, 88: 042508.
[10] Huang Q, Li J, et al. J. Appl. Phys., 2001, 90: 2924--2929.
[11] Subhrangsu Taran, S. Karmakar, Sandip Chatterjee, et al. J. Appl. Phys., 2006, 99: 073703.
[12] Gupta S, Ranjit R, et al. Appl. Phys. Lett., 2001, 78: 362--364.
[13] Wang X L, Dou S X, et al. Appl. Phys. Lett., 1998, 73: 396--398.
[14] Moshnyaga V, Damaschke B, Shapoval O, et al. Nat. Mate., 2003, 2: 247--252.
[15] Helman J S, Abelest B, et al. Phys. Rev. Lett., 1976, 37: 1429--1432.
Options
Outlines

/

〈 〉