Tunneling magnetoresistance in Co-ZrO{sub 2} granular thin films

Journal Article · Sun Jan 15 04:00:00 EST 2006 · Physical Review. B, Condensed Matter and Materials Physics

DOI:https://doi.org/10.1103/PHYSREVB.73.0· OSTI ID:20787856

Hattink, B J; Garcia del Muro, M; Konstantinovic, Z; Batlle, X; Labarta, A; Varela, M ^[1]

---

1. Departament de Fisica Fonamental, Universitat de Barcelona, Avinguda Diagonal 647, 08028 Barcelona (Spain)

Granular films composed of well defined nanometric Co particles embedded in an insulating ZrO{sub 2} matrix were prepared by pulsed laser deposition in a wide range of Co volume concentrations (0.15<x<0.43). High-resolution transmission electron microscopy (TEM) showed very sharp interfaces between the crystalline particles and the amorphous matrix. Narrow particle size distributions were determined from TEM and by fitting the low-field magnetic susceptibility and isothermal magnetization in the paramagnetic regime to a distribution of Langevin functions. The magnetic particle size varies little for Co volume concentrations x<0.32 and increases as the percolation limit is approached. The tunneling magnetoresistance (TMR) was successfully reproduced using the Inoue-Maekawa model. The maximum value of TMR was temperature-independent within 50-300 K, and largely increased at low T, suggesting the occurrence of higher-order tunneling processes. Consequently, the tunneling conductance and TMR in clean granular metals are dominated by the Coulomb gap and the inherent particle size distribution.

• OSTI ID: 20787856
• Journal Information: Physical Review. B, Condensed Matter and Materials Physics, Journal Name: Physical Review. B, Condensed Matter and Materials Physics Journal Issue: 4 Vol. 73; ISSN 1098-0121
• Country of Publication: United States
• Language: English

Related Subjects

75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COBALT
DISTRIBUTION
ENERGY BEAM DEPOSITION
FERROMAGNETIC MATERIALS
GRANULAR MATERIALS
INTERFACES
LASER RADIATION
MAGNETIC FIELDS
MAGNETIC SUSCEPTIBILITY
MAGNETIZATION
MAGNETORESISTANCE
NANOSTRUCTURES
PARAMAGNETISM
PARTICLE SIZE
PULSED IRRADIATION
THIN FILMS
TRANSMISSION ELECTRON MICROSCOPY
TUNNEL EFFECT
ZIRCONIUM OXIDES