Vanadium trapped by oblique nano-sheets to preserve the anisotropy in Co-V thin films at high temperature
Fecha
2022Autor
Versión
Acceso abierto / Sarbide irekia
Tipo
Artículo / Artikulua
Versión
Versión publicada / Argitaratu den bertsioa
Identificador del proyecto
Impacto
|
10.1016/j.jallcom.2022.164950
Resumen
In this study, oriented nano-sheets generated during the growth of cobalt-rich Co–V and Co–Zn thin films
induced a large anisotropy in the magnetic and transport properties. The regular nano-sheets were tilted
52–54 deg. with respect to the substrate plane, ≈ 3.0–4.0 nm thick, ≈ 30–100 nm wide, and ≈ 200–300 nm
long, with an inter-sheet distance of ≈ 0.9–1.2 nm. In spite of the different micro ...
[++]
In this study, oriented nano-sheets generated during the growth of cobalt-rich Co–V and Co–Zn thin films
induced a large anisotropy in the magnetic and transport properties. The regular nano-sheets were tilted
52–54 deg. with respect to the substrate plane, ≈ 3.0–4.0 nm thick, ≈ 30–100 nm wide, and ≈ 200–300 nm
long, with an inter-sheet distance of ≈ 0.9–1.2 nm. In spite of the different microstructures of the two kinds
of samples where the Co–V films were amorphous, whereas the Co–Zn films showed a growth of Zn nanocrystals, the oblique nano-sheet morphology conferred noticeable shape anisotropy to both specimens.
This anisotropy resulted in an in-plane uniaxial magnetic anisotropy. The changes in the nano-morphology
caused by thermal treatments, and hence in their anisotropic properties, were studied. While the Co–V
samples retained or increased their magnetic and transport anisotropies, this anisotropic behavior vanished
for the annealed Co–Zn films. High resolution transmission electron microscopy, HRTEM, including chemical analysis at the nano-scale, and the dependence of the anisotropic resistance on temperature allowed
to establish the nature and the activation energy spectra of the atomic relaxation processes during heating.
These processes displayed a single peak at 1.63 eV for the Co–V and two peaks at 1.67 and 2.0 eV for the
Co–Zn. These spectra and their singularities were associated to the changes induced in the nano-morphology of the films by thermal treatments. The Co–V films retained their nano-sheet morphology almost
up to 500 ºC; the Co–Zn films lost their nano-sheets at 290 ºC. The thermal stability exhibited by the Co–V
films makes them useful for applications in ultra high frequency, optical, magnetostrictive and magnetoelectric devices. [--]
Materias
Thin films,
Nano-fabrications,
Anisotropy,
Electrical transport,
Scanning tunnelling microscopy, STM,
Transmission electron microscopy, TEM,
Electron energy loss spectroscopy, EELS
Editor
Elsevier
Publicado en
Journal of Alloys and Compounds 911 (2022) 164950
Departamento
Universidad Pública de Navarra. Departamento de Ciencias /
Nafarroako Unibertsitate Publikoa. Zientziak Saila /
Universidad Pública de Navarra/Nafarroako Unibertsitate Publikoa. Institute for Advanced Materials and Mathematics - INAMAT2
Versión del editor
Entidades Financiadoras
C. F., J. V., and V. M. acknowledge the financial support of the
Public University of Navarre. C.M. and M.R.I. acknowledge the financial support from the Spanish Ministerio de Economía y
Competitividad in the project MAT2017–82970-C1 and C2-R and
from the Aragón Regional project E26. Open access funding provided
by Universidad Pública de Navarra.