Room-temperature ferromagnetism in manganese doped reduced rutile titanium dioxide thin films
25 May 2004-Journal of Applied Physics (American Institute of Physics)-Vol. 95, Iss: 11, pp 7384-7386
TL;DR: In this article, the properties of single phase and reduced rutile-type thin films were investigated and it was shown that they are single-phase and reduced-rutile type.
Abstract: MnxTi1−xO2−δ (x=0.02–0.12) thin films grown on α-Al2O3 substrates by pulsed-laser deposition have been investigated. X-ray diffraction and transmission electron microscopy results indicate that the films are single phase and reduced rutile-type. Superconducting quantum interference device magnetometer measurements show the films are ferromagnetic at room temperature with nonzero coercivity up to 170 Oe. The saturation magnetization of the reduced films is as high as 0.83 μB per Mn atom at room temperature. The temperature dependence of the resistivity shows semiconducting behavior with p-type carriers. The nature of the p-type conduction and its significance to the ferromagnetism are discussed.
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TL;DR: The electron spin resonance spectra of the Mn doped TiO 2 showed peaks at g ǫ = 1.99 and 4.39, characteristic of Mn 2+ state as mentioned in this paper.
112 citations
TL;DR: In this article, dc-magnetization, electronic structural, and Raman investigations of Ti1−xMnxO2 (x = 0.00, 0.10, and 0.15) thin films deposited on fused-quartz substrate by a simple and cost effective spray pyrolysis technique have been reported.
Abstract: In this work dc-magnetization, electronic structural, and Raman investigations of Ti1−xMnxO2 (x = 0.00, 0.05, 0.10, and 0.15) thin films deposited on fused-quartz substrate by a simple and cost effective spray pyrolysis technique have been reported. X-ray diffraction revealed the formation of pure anatase TiO2 phase devoid of elemental Mn clusters in all the Mn incorporated TiO2 films. It is established by x-ray photoelectron spectroscopic (XPS) measurements that Ti ions substituted by Mn ions in both divalent and trivalent states in the TiO2 matrix. No peak corresponding to Mn+4 could be evidenced by XPS. The Raman study has further established the formation of TiO2 in anatase structure in both pure TiO2 and Mn-doped TiO2 films. The Ti1−xMnxO2 films with x ≥ 0.05 exhibit ferromagnetic ordering at room temperature which arises most likely due to formation of bound magnetic polarons.
98 citations
TL;DR: In this paper, the magnetism and electronic structures of C-doped ZnS (zinc-blende structure) were studied using the full-potential linearized augmented plane wave method.
Abstract: Using the full-potential linearized augmented plane wave method, we study the magnetism and electronic structures of C-doped ZnS (zinc-blende structure). Calculations indicate that C can induce stable ferromagnetic ground state in ZnS hosts. The magnetic moment of the 64-atom supercell (containing one C(S) defect) is 2.00 mu(B). Low formation energy implies ZnS(0.96 875)C(0.03 125) can be fabricated experimentally. Electronic structures show C-doped ZnS is p-type half-metallic ferromagnetic semiconductor and hole-mediated double exchange is responsible for the ferromagnetism. Relative shallow acceptor levels indicate C-doped ZnS is ionized easily at working temperatures. Several doped configurations calculations suggest ferromagnetic couplings exist between the doped carbon atoms.
92 citations
TL;DR: Paramagnetic and ferromagnetic behaviours at room temperature were observed and they are discussed also in connection with the magnetic properties of undoped TiO(2) crystals.
Abstract: Single crystals of TiO2 rutile doped with Cr, Mn, Fe, Co, Ni, and Cu were grown with the flux method in a Na2B4O7 melt The samples, checked in their structural and phase homogeneity by x-ray diffraction and micro-Raman spectroscopy, were single-phase needle-shaped crystals several millimetres long Paramagnetic and ferromagnetic behaviours at room temperature were observed and they are discussed also in connection with the magnetic properties of undoped TiO2 crystals
51 citations
SIDI1
TL;DR: In this article, the magnetic properties of half-heusler XCsBa compounds were investigated using the full potential linear-augmented-plane waves method. But the most important property is that the ferromagnetism is originated from the polarization of the p-X orbitals with an sp-hybridization.
48 citations
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TL;DR: Zener's model of ferromagnetism, originally proposed for transition metals in 1950, can explain T(C) of Ga(1-)(x)Mn(x)As and that of its II-VI counterpart Zn(1)-Mn (x)Te and is used to predict materials with T (C) exceeding room temperature, an important step toward semiconductor electronics that use both charge and spin.
Abstract: Ferromagnetism in manganese compound semiconductors not only opens prospects for tailoring magnetic and spin-related phenomena in semiconductors with a precision specific to III-V compounds but also addresses a question about the origin of the magnetic interactions that lead to a Curie temperature (T(C)) as high as 110 K for a manganese concentration of just 5%. Zener's model of ferromagnetism, originally proposed for transition metals in 1950, can explain T(C) of Ga(1-)(x)Mn(x)As and that of its II-VI counterpart Zn(1-)(x)Mn(x)Te and is used to predict materials with T(C) exceeding room temperature, an important step toward semiconductor electronics that use both charge and spin.
7,062 citations
TL;DR: In this paper, the physical properties of diluted magnetic semiconductors (DMS) of the type AII1−xMnxBVI (e.g., Cd1−mnxSe, Hg 1−mnsTe) were reviewed.
Abstract: We review the physical properties of diluted magnetic semiconductors (DMS) of the type AII1−xMnxBVI (e.g., Cd1−xMnxSe, Hg1−xMnxTe). Crystallographic properties are discussed first, with emphasis on the common structural features which these materials have as a result of tetrahedral bonding. We then describe the band structure of the AII1−xMnxBVI alloys in the absence of an external magnetic field, stressing the close relationship of the sp electron bands in these materials to the band structure of the nonmagnetic AIIBVI ‘‘parent’’ semiconductors. In addition, the characteristics of the narrow (nearly localized) band arising from the half‐filled Mn 3d5 shells are described, along with their profound effect on the optical properties of DMS. We then describe our present understanding of the magnetic properties of the AII1−xMnxBVI alloys. In particular, we discuss the mechanism of the Mn++‐Mn++ exchange, which underlies the magnetism of these materials; we present an analytic formulation for the magnetic susc...
2,895 citations
TL;DR: The observation of transparent ferromagnetism in cobalt-doped anatase thin films with the concentration of cobalt between 0 and 8% is reported, indicating the existence of ferromagnetic long-range ordering.
Abstract: Dilute magnetic semiconductors and wide gap oxide semiconductors are appealing materials for magnetooptical devices. From a combinatorial screening approach looking at the solid solubility of transition metals in titanium dioxides and of their magnetic properties, we report on the observation of transparent ferromagnetism in cobalt-doped anatase thin films with the concentration of cobalt between 0 and 8%. Magnetic microscopy images reveal a magnetic domain structure in the films, indicating the existence of ferromagnetic long-range ordering. The materials remain ferromagnetic above room temperature with a magnetic moment of 0.32 Bohr magnetons per cobalt atom. The film is conductive and exhibits a positive magnetoresistance of 60% at 2 kelvin.
2,302 citations
TL;DR: In this article, a new GaAs-based diluted magnetic semiconductor, (Ga,Mn)As, was prepared by molecular beam epitaxy and the lattice constant was determined by x-ray diffraction and shown to increase with the increase of Mn composition, x.
Abstract: A new GaAs‐based diluted magnetic semiconductor, (Ga,Mn)As, was prepared by molecular beam epitaxy. The lattice constant of (Ga,Mn)As films was determined by x‐ray diffraction and shown to increase with the increase of Mn composition, x. Well‐aligned in‐plane ferromagnetic order was observed by magnetization measurements. Magnetotransport measurements revealed the occurrence of anomalous Hall effect in the (Ga,Mn)As layer.
2,072 citations
TL;DR: In this article, a 3d transition metal-doped ZnO films (n-type Zn1−xMxO) were formed on sapphire substrates using a pulsed-laser deposition technique, and their magnetic and electric properties were examined.
Abstract: 3d-transition-metal-doped ZnO films (n-type Zn1−xMxO (x=005–025): M=Co, Mn, Cr, Ni) are formed on sapphire substrates using a pulsed-laser deposition technique, and their magnetic and electric properties are examined The Co-doped ZnO films showed the maximum solubility limit Some of the Co-doped ZnO films exhibit ferromagnetic behaviors with the Curie temperature higher than room temperature The magnetic properties of Co-doped ZnO films depend on the concentration of Co ions and carriers
1,852 citations