Phase transitions and magnetocaloric and transport properties in off-stoichiometric GdNi{sub 2}Mn{sub x}

Journal Article · Thu Jan 28 00:00:00 EST 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4940877· OSTI ID:22494938

Aryal, Anil; Quetz, Abdiel; Pandey, Sudip; Dubenko, Igor; Mazumdar, Dipanjan; Ali, Naushad ^[1]; Samanta, Tapas; Stadler, Shane ^[2]

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1. Department of Physics, Southern Illinois University, Carbondale, Illinois 62901 (United States)
2. Department of Physics and Astronomy, Louisiana State University, Baton Rouge, Louisiana 70803 (United States)

The structural, magnetic, magnetocaloric, transport, and magnetoresistance properties of the rare-earth intermetallic compounds GdNi{sub 2}Mn{sub x} (0.5 ≤ x ≤ 1.5) have been studied. The compounds with x = 0.5 and 0.6 crystallize in the cubic MgCu{sub 2} type phase, whereas samples with x ≥ 0.8 form a mixed MgCu{sub 2} and rhombohedral PuNi{sub 3} phase. A second order magnetic phase transition from a ferromagnetic to paramagnetic state was observed near the Curie temperature (T{sub C}). The GdNi{sub 2}Mn{sub x} (0.5 ≤ x ≤ 1.5) compounds order in a ferrimagnetic structure in the ground state. The largest observed values of magnetic entropy changes (at T{sub C} for ΔH = 5T) were 3.9, 3.5, and 3.1 J/kg K for x = 0.5, 0.6, and 0.8, respectively. The respective relative values of the cooling power were 395, 483, and 220 J/kg. These values are greater than some well-known prototype magnetocaloric materials such as Gd (400 J/kg) and Gd{sub 5}Si{sub 2}Ge{sub 2} (240 J/kg). Analysis of the resistivity data showed a T{sup 2} dependence at low temperatures, suggesting strong electron-phonon interactions, whereas at higher temperatures s-d scattering was dominated by the electron-phonon contribution, resulting in a slow increase in resistivity. Magnetoresistance values of ∼−1.1% were found for x = 0.5 near T{sub C}, and −7% for x = 1.5 near T = 80 K.

• OSTI ID: 22494938
• Journal Information: Journal of Applied Physics, Vol. 119, Issue 4; Other Information: (c) 2016 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
COOLING
CURIE POINT
ELECTRON-PHONON COUPLING
ENTROPY
GROUND STATES
INTERMETALLIC COMPOUNDS
MAGNETORESISTANCE
MATERIALS
PARAMAGNETISM
PHASE TRANSFORMATIONS
PHONONS
RARE EARTHS
SCATTERING
STOICHIOMETRY
TRIGONAL LATTICES