Magnetism in Gd-W films

Journal Article · Thu May 01 00:00:00 EDT 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2838462· OSTI ID:21137247

Gadioli, Giovana Z; Rouxinol, Francisco P; Gelamo, Rogerio V; Santos, Adenilson O. dos; Cardoso, Lisandro P; Bica de Moraes, Mario A ^[1]

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1. Instituto de Fisica Gleb Wataghin, Universidade Estadual de Campinas, 13083-970 Campinas, Sao Paulo (Brazil)

Vapor condensation techniques are useful to prepare magnetic alloys whose components have low or even negligible equilibrium mutual solubility. In this work, one of these techniques--sputtering--was used to obtain Gd{sub x}W{sub 1-x} alloys whose magnetic properties were investigated as a function of the Gd atomic concentration x. Gadolinium and various Gd-based alloys are promising materials for magnetic refrigeration and this was one of the motivations for this study. The Gd{sub x}-W{sub 1-x} films were sputter deposited from Gd and W targets with x ranging from 0 to 1 as determined by x-ray energy-dispersive spectroscopic analyses. X-ray diffraction patterns indicate that crystalline structures were formed at low and high Gd concentrations, while at intermediate concentrations, the films were amorphous. Magnetization measurements, performed as a function of temperature and with static and alternating applied fields, reveal a spin glasslike behavior in all the W-containing samples for temperatures below the freezing temperature T{sub f}. For low and intermediate Gd concentrations, and for T>T{sub f}, the films were paramagnetic, while a ferromagnetic phase was observed in the Gd-W alloy of the highest Gd content. The magnetocaloric effect was investigated from the magnetization isotherms M versus H, from which the isothermal magnetic entropy variation {delta}S{sub M} as a function of T, for the removal of an applied field of 50 kOe, was determined. It was observed that the maximum value of {delta}S{sub M} for each {delta}S{sub M} versus T curve and the temperature at which these maxima occur, are strongly dependent on x.

• OSTI ID: 21137247
• Journal Information: Journal of Applied Physics, Vol. 103, Issue 9; Other Information: DOI: 10.1063/1.2838462; (c) 2008 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ADIABATIC DEMAGNETIZATION
CHEMICAL ANALYSIS
DEPOSITION
ENTROPY
FERROMAGNETIC MATERIALS
FREEZING
GADOLINIUM
GADOLINIUM ALLOYS
ISOTHERMS
MAGNETIC PROPERTIES
MAGNETIZATION
PARAMAGNETISM
REFRIGERATION
SPIN GLASS STATE
SPUTTERING
TEMPERATURE DEPENDENCE
THIN FILMS
TUNGSTEN ALLOYS
VAPOR CONDENSATION
X-RAY DIFFRACTION