Large magnetoresistance in intermetallic compounds ( = , and )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 ( = , and ) compounds (tetragonal, space group P4/mnc) have been carried out in the temperature range of 2-300, 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 whereas Mn2 is found to magnetically order at ( , 86, 78 and , 34, 16 for R = Tb, Dy and Ho compounds, respectively). Magnetoresistance measurements reveal large negative MR values of about 50% near at 9 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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