Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（C...Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（Cu2O）1-x deposition. Room-temperature ferromagnetism（FM） is found in all of the samples. The saturated magnetization increases at first and then decreases with the decrease of x. The photoluminescence spectra show that the magnetization is closely correlated with the Cu vacancies in the Cux（Cu2O）1-x granular films. Fundamentally, the FM could be understood by the Stoner model based on the charge transfer mechanism. These results may provide solid evidence and physical insights on the origin of FM in the Cu2O-based oxides diluted magnetic semiconductors, especially for systems without intentional magnetic atom doping.展开更多
The segregation behavior of α-Fe particles in Cu-Fe film prepared by magnetron sputtering was studied by X-ray scattering and X-ray diffraction. The results show that the roughness of the film surface increases with ...The segregation behavior of α-Fe particles in Cu-Fe film prepared by magnetron sputtering was studied by X-ray scattering and X-ray diffraction. The results show that the roughness of the film surface increases with the sputtering time increasing. The as-sputtered films are super saturation solid solution of Cu-Fe. After annealing at 500℃, α-Fe particle can be segregated from the Cu matrix. The orientations α-Fe particles in the annealed film without magnetic field are random. But the clear texture of α-Fe particles in the annealed film with magnetic field is formed, and the 〈001〉 direction of α-Fe particles tends to be parallel to the magnetic field direction.展开更多
The γ＇-Fe4N films on Cu underlayers are deposited on the glass and Si substrates by dc magnetron reactive sputtering. The effects of Cu underlayer on the structure, morphology and magnetic properties of the γ＇-Fe4...The γ＇-Fe4N films on Cu underlayers are deposited on the glass and Si substrates by dc magnetron reactive sputtering. The effects of Cu underlayer on the structure, morphology and magnetic properties of the γ＇-Fe4N films are studied. The single-phase γ＇-Fe4N films with Cu underlayers on the glass substrate are obtained, while the mixture of Fe and γ＇-Fe4N is observed on the Si substrate. In comparison with the films without Cu underlayers, the grains of the films with Cu underlayers exhibit a non-uniform size distribution and give rise to a rougher surface. The magnetic measurements indicate that the γ＇-Fe4N films show a good soft ferromagnetic behavior. The enhanced coercivity in the films with Cu underlayers is observed due to the deterioration of the crystallographic structure as well as the rougher surface.展开更多
Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples...Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 （10 MHz）, Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices.展开更多
Fe-Cu thin films of 0.2 mum in thickness with different Cu contents wereprepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputteringparameters, including Ar gas pressure and input rf powe...Fe-Cu thin films of 0.2 mum in thickness with different Cu contents wereprepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputteringparameters, including Ar gas pressure and input rf power, on the structure and magnetic propertieswas investigated. It was found that when the power is lower than 70W, the structure of the filmsremained single bcc-Fe phase with Cu solubility of up to 50at. percent. TEM observations for thebcc-Fe phase showed that the grain size was in the nanometer range of less than 20nm. The coercivityof Fe- Cu films was largely affected by not only Ar gas pressure but also rf power, and reachedabout 2.5Oe in the pressure of 0.67-6.67Pa and in the power of less than 100W. In addition,saturation magnetization, with Cu content less than 60at. percent, was about proportional to thecontent of bcc-Fe. When Cu content was at 60at. percent, however, saturation magnetization was muchsmaller than its calculation value.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11104148,51101088,and 51171082)the Tianjin Natural Science Foundation,China(Grant Nos.14JCZDJC37700 and 13JCQNJC02800)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20110031110034)the Fundamental Research Funds for the Central Universities,China
文摘Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（Cu2O）1-x deposition. Room-temperature ferromagnetism（FM） is found in all of the samples. The saturated magnetization increases at first and then decreases with the decrease of x. The photoluminescence spectra show that the magnetization is closely correlated with the Cu vacancies in the Cux（Cu2O）1-x granular films. Fundamentally, the FM could be understood by the Stoner model based on the charge transfer mechanism. These results may provide solid evidence and physical insights on the origin of FM in the Cu2O-based oxides diluted magnetic semiconductors, especially for systems without intentional magnetic atom doping.
文摘The segregation behavior of α-Fe particles in Cu-Fe film prepared by magnetron sputtering was studied by X-ray scattering and X-ray diffraction. The results show that the roughness of the film surface increases with the sputtering time increasing. The as-sputtered films are super saturation solid solution of Cu-Fe. After annealing at 500℃, α-Fe particle can be segregated from the Cu matrix. The orientations α-Fe particles in the annealed film without magnetic field are random. But the clear texture of α-Fe particles in the annealed film with magnetic field is formed, and the 〈001〉 direction of α-Fe particles tends to be parallel to the magnetic field direction.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61434002,61204097,11274214 and 51301099the National High-Tech Research and Development Program of China under Grant No 2014AA032904+1 种基金the Chang Jiang Scholars and Innovative Team Development Plan by the Ministry of Education under Grant No IRT1156the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant Nos 20121404130001 and 20121404120003
文摘The γ＇-Fe4N films on Cu underlayers are deposited on the glass and Si substrates by dc magnetron reactive sputtering. The effects of Cu underlayer on the structure, morphology and magnetic properties of the γ＇-Fe4N films are studied. The single-phase γ＇-Fe4N films with Cu underlayers on the glass substrate are obtained, while the mixture of Fe and γ＇-Fe4N is observed on the Si substrate. In comparison with the films without Cu underlayers, the grains of the films with Cu underlayers exhibit a non-uniform size distribution and give rise to a rougher surface. The magnetic measurements indicate that the γ＇-Fe4N films show a good soft ferromagnetic behavior. The enhanced coercivity in the films with Cu underlayers is observed due to the deterioration of the crystallographic structure as well as the rougher surface.
基金the National Natural Science Foundation of China (No. 90607021).
文摘Ni0.4Cu0.2Zn0.4Fe2O4 thin films were fabricated on Si substrates by using the sol-gel method and rapid thermal annealing （RTA）, and their magnetic properties and crystalline structures were investigated. The samples calcined at and above 600 ℃ have a single-phase spinel structure and the average grain size of the sample calcined at 600 ℃ is about 20 nm. The initial permeability μi, saturation magnetization M and coercivity H of the samples increase with the increasing calcination temperature. The sample calcined at 600 ℃ exhibits an excellent soft magnetic performance, which has μi=33.97 （10 MHz）, Hc=15.62 Oe and Ms=228.877 emu/cm^3. Low-temperature annealing can enhance the magnetic properties of the samples. The work shows that using the sol-gel method in conjunction with RTA is a promising way to fabricate integrated thin-film devices.
基金This research is sponsored by the National Natural Science Foundation of China (Grant No.69971006).
文摘Fe-Cu thin films of 0.2 mum in thickness with different Cu contents wereprepared by using r.f. magnetron sputtering onto glass substrate. The effect of sputteringparameters, including Ar gas pressure and input rf power, on the structure and magnetic propertieswas investigated. It was found that when the power is lower than 70W, the structure of the filmsremained single bcc-Fe phase with Cu solubility of up to 50at. percent. TEM observations for thebcc-Fe phase showed that the grain size was in the nanometer range of less than 20nm. The coercivityof Fe- Cu films was largely affected by not only Ar gas pressure but also rf power, and reachedabout 2.5Oe in the pressure of 0.67-6.67Pa and in the power of less than 100W. In addition,saturation magnetization, with Cu content less than 60at. percent, was about proportional to thecontent of bcc-Fe. When Cu content was at 60at. percent, however, saturation magnetization was muchsmaller than its calculation value.
