Europhys. Lett.
Volume 69, Number 3, February 2005
Page(s) 454 - 460
Section Condensed matter: electronic structure, electrical, magnetic, and optical properties
Published online 24 December 2004
Europhys. Lett., 69 (3), pp. 454-460 (2005)
DOI: 10.1209/epl/i2004-10358-3

Large magnetoresistance in the magnetically ordered state as well as in the paramagnetic state near $\mth{300}$ $\un{K}$ in an intermetallic compound, $\chem{Gd_{7}Rh_{3}}$

K. Sengupta, S. Rayaprol and E. V. Sampathkumaran

Tata Institute of Fundamental Research - Homi Bhabha Road Colaba, Mumbai-400005, India

received 12 October 2004; accepted in final form 22 November 2004
published online 24 December 2004

We report the response of electrical resistivity $\rho$ to the application of magnetic fields ( H) up to 140 $\un{kOe}$ in the temperature interval 1.8-300 $\un{K}$ for the compound $\chem{Gd_{7}Rh_{3}}$, ordering antiferromagnetically below 150 $\un{K}$. We find that there is an unusually large decrease of $\rho$ for moderate values of H in the close vicinity of room temperature, uncharacteristic of paramagnets, with the magnitude of the magnetoresistance increasing with decreasing temperature as though the spin-order contribution to $\rho$ were temperature dependent. In addition, this compound exhibits giant-magnetoresistance behaviour at rather high temperatures (above 77 $\un{K}$) in the magnetically ordered state due to a metamagnetic transition.

75.47.De - Giant magnetoresistance.
72.15.-v - Electronic conduction in metals and alloys.
75.50.-y - Studies of specific magnetic materials.

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