Magnetocaloric and magnetotransport properties on R2Ni2Sn compounds (R=Ce, Nd, Sm, Gd, and Tb)

Journal Article · Mon May 12 04:00:00 EDT 2008 · Physical Review B

OSTI ID:977135

Kumar, P; Singh, N; Suresh, K; Nigam, A

We report a detailed magnetic, magnetocaloric, and magnetotransport study on R{sub 2}Ni{sub 2}Sn compounds with different rare earths. The magnetic state of these compounds is found to be complex because of the coexistence of ferromagnetic and antiferromagnetic components. These compounds show phenomena such as multiple magnetic transitions, nonsaturation of magnetization, and metamagnetic transitions. Analysis of the zero-field heat capacity data shows that the magnetic entropy is less than the theoretical value, indicating the presence of some moment on Ni. Schottky anomaly is present in the magnetic heat capacity data of Sm{sub 2}Ni{sub 2}Sn. The temperature variation of magnetocaloric effect reflects the magnetization behavior. Tb{sub 2}Ni{sub 2}Sn and to a less extent Gd{sub 2}Ni{sub 2}Sn show oscillatory magnetocaloric effect. The variation of magnetocaloric effect is correlated with the ferromagnetic-antiferromagnetic phase coexistence. The electrical resistivity analysis has shown that the electron-magnon scattering is prominent at low temperature, while phonon scattering modified by the s-d interaction is crucial at high temperatures. The magnetoresistance is very large in Ce{sub 2}Ni{sub 2}Sn and shows a quadratic dependence on the field, implying the role of spin fluctuations in determining the transport behavior. Large magnetoresistance has been observed in other compounds as well.

• Research Organization: Ames Laboratory (AMES), Ames, IA (United States)
• Sponsoring Organization: USDOE Office of Science (SC)
• DOE Contract Number: AC02-07CH11358
• OSTI ID: 977135
• Report Number(s): IS-J 7459
• Journal Information: Physical Review B, Journal Name: Physical Review B Journal Issue: 184411 Vol. 77; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ELECTRIC CONDUCTIVITY
ENTROPY
FLUCTUATIONS
MAGNETIZATION
MAGNETORESISTANCE
PHONONS
RARE EARTHS
SCATTERING
SPECIFIC HEAT
SPIN
TRANSPORT