Size Effects on the Spin Density Wave in Cr Films
15 Aug 1977-Journal of the Physical Society of Japan (THE PHYSICAL SOCIETY OF JAPAN)-Vol. 43, Iss: 2, pp 468-476
TL;DR: In this article, a discussion is made on the extremely large anomaly in the resistivity of films deposited at 20°C, which consist of very fine sub-grains with an average diameter smaller than the period of the spin density wave.
Abstract: Thin films of Cr were deposited on glass substrates at 20°C, 50°C, 100°C and 250°C in a vacuum of about 5×10 -5 Torr. Their structural and electrical properties were investigated by means of the transmission-electron microscopy, electron diffraction and resistivity measurement. Films deposited at 100°C show the same anomaly in the electrical resistivity as that observed in the plastically deformed Cr. The Neel temperature T N , obtained from the resistivity anomaly, increases with decreasing film thickness. This shift in T N , being related to the tension due to the residual strain developed in the films, is explained in terms of the variation of the critical yield stress. In relation to the uncommensurate-commensurate transition of the spin density wave, a discussion is made on the extremely large anomaly in the resistivity of films deposited at 20°C, which consist of very fine sub-grains with an average diameter smaller than the period of the spin density wave.
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TL;DR: In this paper, the electrical resistivities of electron beam deposited and sputter deposited chromium thin films (25-500 nm) on glass and alumina substrates are correlated with the structural characteristics of the films determined by X-ray diffraction, scanning electron microscope and Auger electron spectrometer.
59 citations
TL;DR: In this paper, the electrical resistivities of single-layered Cu and Cr films and Cu/Cr multilayered thin films sputter on Si substrates were evaluated as a function of layer thicknesses ranging from 2.5 to 150 nm in the temperature range of 4-325 K.
Abstract: Parallel (in-plane) electrical resistivities of single-layered Cu and Cr films, and Cu/Cr multilayered thin films sputter deposited on Si substrates were evaluated as a function of layer thicknesses ranging from 2.5 to 150 nm in the temperature range of 4–325 K. The resistivity of the multilayers at a given temperature increased and residual resistivity ratio decreased with decreasing layer thicknesses. At 300 K, the resistivity of a 1 μm thick Cu film was approximately equal to the bulk value, but the resistivity of the Cr film was an order of magnitude higher than that of bulk Cr. The microstructures of the multilayers and the single-layered Cu and Cr thin films were characterized by transmission electron microscopy. For layer thicknesses ranging from 2.5 to 150 nm, the multilayers exhibited sharp, planar interfaces between the two phases. The individual Cu and Cr layers were nanocrystalline with near-equiaxed grains in Cu and columnar grains in Cr. The dependence of electrical resistivity on the layer ...
38 citations
TL;DR: In this article, it was shown that the new modification of chromium, referred to as NMCr, cannot be the metal itself, since it has different reactive properties, such as a suboxide with a primitive cubic cell and a hydrated oxyhydroxide with a rhombohedral structure.
Abstract: Chromium thin films obtained by evaporation in a vacuum bell-jarr have different reactive properties. In order to determine these ones six techniques are used: X-rays and electron diffractions to study the crystallographical structures; EELS, AES, ESCA, and GXR (grazing X-ray reflection) methods in order to approach the chemical composition. The results permit to show the formation of compounds such as a suboxide (Cr3O) with a primitive cubic cell (A-15 type) and a hydrated oxyhydroxide with a rhombohedral structure. This study leads to show that the „new modification of chromium”, as „NMCr”, cannot be the metal itself.
Les couches minces de chrome obtenues par evaporation sous vide presentent des proprietes reactives diverses. Afin de les determiner nous avons utilise six techniques differentes: la diffraction de rayons-X et la diffraction electronique pour etudier les structures cristallographiques; et les methodes de mesures: EELS, AES, ESCA et GXR (rayons-X rasants par reflection) pour approcher la composition chimique. Les resultats ont permis de mettre en evidence la formation de plusieurs composes: un sous-oxyde de composition „Cr3O” de structure cubique primitive (type A-15) et un oxyhydroxyde hydrate de structure rhomboedrique. Cette etude a conduit a montrer que la „nouvelle modification du chrome”, appelee „NMCr”, ne peut etre assimilee au metal luiměme.
29 citations
TL;DR: In this paper, the electrical resistivity of polycrystalline films of Corning glass 7059 has been studied in situ as a function of temperature (T), film thickness (t), and the above preparation variables.
Abstract: We have prepared thin (50–1500 A) polycrystalline films of Cr by vacuum (10−8 Torr) evaporation methods using the deposition rate on Corning glass 7059 and its temperature as experimental parameters. Electrical resistivity (ρ) of these films has been studied in situ as a function of temperature (T), film thickness (t), and the above preparation variables. Our films exhibit well‐definied anomalies at the Neel temperature which is strongly dominated by internal stresses. The ρ vs T curves are briefly compared with those of other investigators.
20 citations
TL;DR: In this paper, the surface magnetism of He 3 atoms in confined geometries, or of transition metal surfaces or more generally when the local surface density of states at the Fermi level is much larger than the bulk one, is reviewed to show the main differences between two and three-dimensional magnetism.
20 citations
References
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TL;DR: In this article, a modele statistique applicable aux phenomenes de filiation radioactive a plusieurs etages is presented, i.e., un modele statisticique applicable to a phenomene global, in fonction des differentes lois des retards aleatoires introduits par le phenomeme de filiations.
Abstract: On etudie un modele statistique applicable aux phenomenes de filiation radioactive a plusieurs etages. Chaque evenement se traduisant par une realisation d'une impulsion aleatoire, on determine les statistiques des deux premiers ordres de la fonction de couverture associee au phenomene global, en fonction des differentes lois des retards aleatoires introduits par le phenomene de filiation.
690 citations
01 Aug 1962
TL;DR: In this paper, the position of the Fermi surface of non-magnetic chromium was estimated based on electron energy levels in body-centred cubic transition metals, and it was shown that almost the whole of this surface is placed so that the introduction of an antiferromagnetic superlattice will lower the electron energy, so that such a structure should be expected to be stable at low temperatures.
Abstract: Recent calculations of electron energy levels in body-centred cubic transition metals are used to estimate the position of the Fermi surface of non-magnetic chromium. It is shown that almost the whole of this surface is placed so that the introduction of an antiferromagnetic superlattice will lower the electron energy, so that such a structure should be expected to be stable at low temperatures, in accordance with observation. The complexity of the magnetic structure is not explained. The shape of the Fermi surfaces for the non-magnetic material is in accord with the properties of molybdenum and tungsten.
351 citations
TL;DR: In this article, a series of transition elements are reported as being antiferromagnetic with temperatures as low as 4.2 K and as high as 100 K, respectively, and the atomic moments for Cr and Mn follow the general trend of the Slater Pauling curve.
Abstract: Neutron diffraction measurements are reported on a series of transition elements as an investigation into their magnetic structures. Scattering data have been taken for W, Mo, Nb, V, Cr, Mn, and Fe at various temperatures as low as 4.2\ifmmode^\circ\else\textdegree\fi{}K, and these data are interpreted in terms of the magnetic structure existing in the pure metals. For the first four-named elements, no magnetic scattering either coherent or incoherent is found. Cr and $\ensuremath{\alpha}\ensuremath{-}\mathrm{M}\mathrm{n}$ are established as being antiferromagnetic with N\'eel temperatures of 475\ifmmode^\circ\else\textdegree\fi{}K and 100\ifmmode^\circ\else\textdegree\fi{}K, respectively. Paramagnetic scattering has been observed in manganese at room temperature, and the atomic moments determined for Cr and Mn follow the general trend of the Slater-Pauling curve. Magnetic superstructure effects and magnetic disorder scattering were looked for in iron and neither was found.
198 citations
181 citations
TL;DR: The temperature dependence of the magnetic contribution to the electrical resistivity can be explained by taking into account only the variation in the number of effective carriers from the introduction of a band gap due to the magnetic ordering as mentioned in this paper.
Abstract: The N\'eel temperature of Cr is found to vary exponentially with volume, which is in support of a two-band model of itinerant antiferromagnetism. The temperature dependence of the magnetic contribution to the electrical resistivity can be explained by taking into account only the variation in the number of effective carriers from the introduction of a band gap ($2\ensuremath{\Delta}$) due to the magnetic ordering. The ratio $\frac{{\ensuremath{\Delta}}_{0}}{k{T}_{\mathrm{N}}}$ is estimated at 2.3 at $P=26$ kbar.
107 citations