We report a systematic study of room-temperature ferromagnetism (RTFM) in pristine MgO thin films in their amorphous and nano-crystalline states. The as deposited dc-sputtered films of pristine MgO on Si substrates using a metallic Mg target in an O₂ containing working gas atmosphere of (N₂ + O₂) are found to be X-ray amorphous. All these films obtained with oxygen partial pressure (P₂) ~10% to 80% while maintaining the same total pressure of the working gas are found to be ferromagnetic at room temperature. The room temperature saturation magnetization (M) value of 2.68 emu/cm³ obtained for the MgO film deposited in P₂ of 10% increases to 9.62 emu/cm³ for film deposited at P₂ of 40%. However, the M values decrease steadily for further increase of oxygen partial pressure during deposition. On thermal annealing at temperatures in the range 600 to 800 °C, the films become nanocrystalline and as the crystallite size grows with longer annealing times and higher temperature, M decreases. Our study clearly points out that it is possible to tailor the magnetic properties of thin films of MgO. The room temperature ferromagnetism in MgO films is attributed to the presence of Mg cation vacancies.
Download full-text PDF |
Source |
|---|---|
| http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5304652 | PMC |
| http://dx.doi.org/10.3390/nano3030486 | DOI Listing |
Publication Analysis
Top Keywords
Similar Publications
Micro Coriolis Mass Flow Sensor with Large Channel Diameter Realized by HNA Wet Etching.
Sensors (Basel)
December 2024
MESA+ Institute for Nanotechnology, University of Twente, 7522 NH Enschede, The Netherlands.
This paper introduces a Coriolis mass flow and density sensor. The sensor is made using Surface Channel Technology (SCT) but with selective wet etching to create the channels. This method forms suspended microfluidic channels with a larger cross-sectional area.
View Article and Find Full Text PDFHigh-Performance Porous Supports Based on Hydroxyl-Terminated Polysulfone and CO/CO-Selective Composite Membranes.
Polymers (Basel)
December 2024
Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory, 1, 119991 Moscow, Russia.
The scope of this work was to develop a thin-film composite (TFC) membrane for the separation of CO/CO mixtures, which are relevant for many processes of gas processing and gasification of carbon-based feedstock. Special attention was given to the development of highly permeable porous polysulfone (PSF) supports (more than 26,000 GPU for CO) since both the selective and support layers contribute significantly to the overall performance of the TFC membrane. The PSF porous support is widely used in commercial and lab-scale TFC membranes, and its porous structure and other exploitation parameters are set during the non-solvent-induced phase separation (NIPS) process.
View Article and Find Full Text PDFEnhancing Resistive Switching in AlN-Based Memristors Through Oxidative AlO Layer Formation: A Study on Preparation Techniques and Performance Impact.
Micromachines (Basel)
December 2024
School of Integrated Circuit, Southeast University, Nanjing 210096, China.
Aluminum nitride (AlN) with a wide band gap (approximately 6.2 eV) has attractive characteristics, including high thermal conductivity, a high dielectric constant, and good insulating properties, which are suitable for the field of resistive random access memory. AlN thin films were deposited on ITO substrate using the radio-frequency magnetron sputtering technique.
View Article and Find Full Text PDFFull Spectrum Electrochromic WO Mechanism and Optical Modulation via Ex Situ Spectroscopic Ellipsometry: Effect of Li Surface Permeation.
Micromachines (Basel)
December 2024
School of Physics, Changchun University of Science and Technology, Changchun 130012, China.
Tungsten oxide (WO) electrochromic devices are obtaining increasing interest due to their color change and thermal regulation. However, most previous work focuses on the absorption or transmission spectra of materials, rather than the optical parameters evolution in full spectrum in the electrochromic processes. Herein, we developed a systematic protocol of ex situ methods to clarify the evolutions of subtle structure changes, Raman vibration modes, and optical parameters of WO thin films in electrochromic processes as stimulated by dosage-dependent Li insertion.
View Article and Find Full Text PDFApplication of Solution-Processed High-Entropy Metal Oxide Dielectric Layers with High Dielectric Constant and Wide Bandgap in Thin-Film Transistors.
Micromachines (Basel)
November 2024
Southwest Institute of Technology and Engineering, Chongqing 400039, China.
High-k metal oxides are gradually replacing the traditional SiO dielectric layer in the new generation of electronic devices. In this paper, we report the production of five-element high entropy metal oxides (HEMOs) dielectric films by solution method and analyzed the role of each metal oxide in the system by characterizing the film properties. On this basis, we found optimal combination of (AlGaTiYZr)O with the best dielectric properties, exhibiting a low leakage current of 1.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!