Transport properties in amorphous U/sub x/-T/sub 1//sub -//sub x/ films (T = Fe, Ni, Gd, Tb, and Yb) (invited)

Journal Article · Mon Nov 14 23:00:00 EST 1988 · J. Appl. Phys.; (United States)

DOI:https://doi.org/10.1063/1.342346· OSTI ID:7017212

Freitas, P P; Plaskett, T S; Moreira, J M; Amaral, V S

We describe the competing magnetic, localization, and phonon effects on the transport properties of amorphous magnetic U/sub x/T/sub 1-//sub x/ films, with T = Fe, Ni, Gd, Tb, and Yb. Amorphous U/sub x/Fe/sub 1-//sub x/ films change from collinear to random ferromagnetism as x increases, and the temperature dependence of the resistivity denotes the competing effects of spin-flip and non-spin-flip exchange scattering processes. The resistivity has a minimum at T/sub f/ rising sharply below this temperature. The sign of the magnetic resistivity and the magnetoresistance indicates >0, while the anisotropic magnetoresistance indicates a local exchange gap. Amorphous U/sub x/Gd/sub 1-//sub x/ and a-U/sub x/Tb/sub 1-//sub x/ are, respectively, spin glasses and random anisotropy dominated systems. The resistivity increases smoothly through T/sub f/ and has a slight upturn at low temperatures that we associate with weak localization. The magnetoresistance is negative in both systems and the anisotropic magnetoresistance is null, although the applied field induces anisotropic behavior in the Tb containing films (asperomagnets). All samples show quadratic and positive field dependence of magnetoresistance well inside the paramagnetic regime, and a linear regime below T/sub f/. At low temperatures and in the a-U/sub x/Gd/sub 1-//sub x/ films, negative (H)/sup 1/2/ and H/sup 2/ regimes occur and are associated with weak localization processes dominated by the inelastic mean free path.

• Research Organization: INESC, R. Alves Redol 9-3, 1000 Lisbon, Portugal
• OSTI ID: 7017212
• Journal Information: J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 64:10; ISSN JAPIA
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
ACTINIDE ALLOYS
ALLOYS
AMORPHOUS STATE
ANISOTROPY
ELECTRIC CONDUCTIVITY
ELECTRICAL PROPERTIES
FERROMAGNETIC MATERIALS
FILMS
GADOLINIUM ALLOYS
IRON ALLOYS
MAGNETIC MATERIALS
MAGNETORESISTANCE
MATERIALS
NICKEL ALLOYS
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
SPIN GLASS STATE
TEMPERATURE DEPENDENCE
TERBIUM ALLOYS
THIN FILMS
URANIUM ALLOYS
YTTERBIUM ALLOYS