Diluted magnetic oxides have evolved into a popular branch of materials science during the last decade. In the first few years, people attributed the ferromagnetism to the magnetic dopants. However, the observat...Diluted magnetic oxides have evolved into a popular branch of materials science during the last decade. In the first few years, people attributed the ferromagnetism to the magnetic dopants. However, the observation of ferromagnetism in undoped HfO2 thin films made it more controversial and promoted extensive research on the ferromagnetism in various undoped oxides. Both of the experimental w-orks and theoretical studies have shown that intrinsic defects in oxide nanomaterials play a crucial role in the origin of such an unexpected ferromagnetism, in spite of some contradicting views which kind of defects is predominant. In the past several years, we have conducted systematic and thorough research on the room temperature ferromagnetism in undoped ZrO2 thin films, and clarif some physics behind it. We firstly prepared undoped ZrO2 thin films by different w-ays, such as Pulsed electron bean deposition, magnetron sputtering, and electron beam evaporation, and successfully obtained ZiO2 thin films wdth different crystalline structure, in particular a pure high-temperature stabilized one, by adjusting some preparation parameters during the deposition process or post-annealing treatment. A phase-dependent ferromagnetism w-as then confinmed to exist in such ZiO2 thin films. Further, w-e conducted exhaustive defect analysis and characterization by X-ray photoelectron spectroscopy, photoluminescence spectra, and electron paramagnetic resonance, respectively, and found the oxygen vacancy, specifically the single ionized oxygen vacancy （Vo＋） , has a remarkable influence on the enhancement of ferromagnetism. Herein, we will review the work in detail on the phase-dependent and oxygen vacancy-enhanced room temperature ferromagnetism in undoped ZrO2 thin films.Keywords Zi thin film ferromagnetism phase-dependent oxygen vacancy展开更多
The ZrO2 thin films deposited on Si (100) were successfully synthesized by solgel process and deposited by using spin-coating technique.The structural properties of ZrO2 thin films were investigated by X-Ray Diffracti...The ZrO2 thin films deposited on Si (100) were successfully synthesized by solgel process and deposited by using spin-coating technique.The structural properties of ZrO2 thin films were investigated by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and electrical properties were studied by conventional techniques like Capacitance-Voltage (C-V) measurement and Current–Voltage (I–V) measurement. The XRD of ZrO2 films shows the films crystallized and exists in two phases at 700℃ calcinations temperature. The C–V characteristics of all the dielectric films that involved distinct inversion, depletion, and accumulation were clearly revealed in MIS structure. I-V characteristics of ZrO2 thin films on Si shows decreased saturation current on calcinations temperatures. The XPS measurement reveals that a zirconium silicate interfacial layer has formed in the ZrO2/Si Systems.展开更多
基金Sponsored by the National Natural Science Foundation of China(Grant No.50931002,51072094 and 51372135)the Ministry of Education of the People’s Republic of China(Grant No.113007A)the Tsinghua University Initiative Scientific Research Program
文摘Diluted magnetic oxides have evolved into a popular branch of materials science during the last decade. In the first few years, people attributed the ferromagnetism to the magnetic dopants. However, the observation of ferromagnetism in undoped HfO2 thin films made it more controversial and promoted extensive research on the ferromagnetism in various undoped oxides. Both of the experimental w-orks and theoretical studies have shown that intrinsic defects in oxide nanomaterials play a crucial role in the origin of such an unexpected ferromagnetism, in spite of some contradicting views which kind of defects is predominant. In the past several years, we have conducted systematic and thorough research on the room temperature ferromagnetism in undoped ZrO2 thin films, and clarif some physics behind it. We firstly prepared undoped ZrO2 thin films by different w-ays, such as Pulsed electron bean deposition, magnetron sputtering, and electron beam evaporation, and successfully obtained ZiO2 thin films wdth different crystalline structure, in particular a pure high-temperature stabilized one, by adjusting some preparation parameters during the deposition process or post-annealing treatment. A phase-dependent ferromagnetism w-as then confinmed to exist in such ZiO2 thin films. Further, w-e conducted exhaustive defect analysis and characterization by X-ray photoelectron spectroscopy, photoluminescence spectra, and electron paramagnetic resonance, respectively, and found the oxygen vacancy, specifically the single ionized oxygen vacancy （Vo＋） , has a remarkable influence on the enhancement of ferromagnetism. Herein, we will review the work in detail on the phase-dependent and oxygen vacancy-enhanced room temperature ferromagnetism in undoped ZrO2 thin films.Keywords Zi thin film ferromagnetism phase-dependent oxygen vacancy
文摘The ZrO2 thin films deposited on Si (100) were successfully synthesized by solgel process and deposited by using spin-coating technique.The structural properties of ZrO2 thin films were investigated by X-Ray Diffraction (XRD), Scanning Electron Microscope (SEM), Fourier Transform Infrared Spectroscopy (FT-IR), and electrical properties were studied by conventional techniques like Capacitance-Voltage (C-V) measurement and Current–Voltage (I–V) measurement. The XRD of ZrO2 films shows the films crystallized and exists in two phases at 700℃ calcinations temperature. The C–V characteristics of all the dielectric films that involved distinct inversion, depletion, and accumulation were clearly revealed in MIS structure. I-V characteristics of ZrO2 thin films on Si shows decreased saturation current on calcinations temperatures. The XPS measurement reveals that a zirconium silicate interfacial layer has formed in the ZrO2/Si Systems.
