Europhys. Lett.
Volume 76, Number 3, November 2006
Page(s) 471 - 476
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 07 October 2006
Europhys. Lett., 76 (3), pp. 471-476 (2006)
DOI: 10.1209/epl/i2006-10290-6

Large magnetoresistance in intermetallic compounds $\chem{R_{2}Mn_{3}Si_{5}}$ ($\chem{R}$ = $\chem{Tb}$, $\chem{Dy}$ and $\chem{Ho}$)

R. Nirmala1, S. K. Malik1, A. V. Morozkin2, Y. Yamamoto3 and H. Hori3

1  Tata Institute of Fundamental Research - Mumbai 400 005 India
2  Department of Chemistry, Moscow State University Moscow, GSP-2, 119992, Russia
3  School of Materials Science, Japan Advanced Institute of Science and Technology - Ishikawa 923-1292, Japan

received 12 August 2006; accepted 12 September 2006
published online 7 October 2006

Magnetization (M) and magnetoresistance (MR) measurements on polycrystalline $\chem{R_{2}Mn_{3}Si_{5}}$ ($\chem{R}$ = $\chem{Tb}$, $\chem{Dy}$ and $\chem{Ho}$) compounds (tetragonal, space group P4/mnc) have been carried out in the temperature range of 2$\un{K}$-300$\un{K}$, in various applied fields. Both, the rare earth and Mn, are found to carry magnetic moments in these compounds. Mn has two sub-lattices (Mn1 and Mn2) that order magnetically at two different temperatures. Rare-earth and Mn1 moments order ferromagnetically at $T_{\ab C1}$ whereas Mn2 is found to magnetically order at $T_{\ab C2}$ ( $T_{\ab C1} = 89\un{K}$, 86$\un{K}$, 78$\un{K}$ and $T_{\ab C2} = 18\un{K}$, 34$\un{K}$, 16$\un{K}$ for R = Tb, Dy and Ho compounds, respectively). Magnetoresistance measurements reveal large negative MR values of about 50% near $T_{\ab C2}$ at 9$\un{T}$ in all these compounds. This giant magnetoresistance is attributed to the spin-dependent scattering effects, competing exchange interactions and the layered structure of these compounds.

71.20.Eh - Rare earth metals and alloys.
72.15.-v - Electronic conduction in metals and alloys.
75.47.-m - Magnetotransport phenomena; materials for magnetotransport.

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