中文摘要：

利用射频磁控溅射的方法，在不同的工作气压（0．2Pa～4．0Pa）下，制备了一系列的本征TiO2薄膜。在2～340K的绝对温度下，测得所有制备态的本征TiO2薄膜均具有铁磁性，2．0Pa工作气压下制备的TiO2薄膜具有最大的室温饱和磁化强度为1．96emu／cm^3。通过TiO2薄膜的X衍射（XRD）图谱观察到，在0．2Pa工作气压下，锐钛矿和金红石结构共存于Ti02多晶薄膜中；随着工作气压的增加，出现了金红石结构向锐钛矿结构的转变；当气压增加到2．0Pa时，TiO2薄膜的晶体结构由多晶态转变成非晶态。利用高分辨率透射电镜（HRTEM）分析TiO2薄膜的晶体结构，通过观察1．2Pa和2．0Pa工作气压下Ti02薄膜的电子衍射花样和HRTEM图，可以清楚地看到多晶态向非晶态的转变。利用分光光度计测试了Ti02薄膜样品的透过率曲线，可见光区平均透过率高于85％，伴随着晶体结构的非晶态转变，光学透过率曲线的吸收边向长波方向移动，光学带隙减小到3．14eV，由此可以证明，增加的结构缺陷是系统铁磁性产生的主要原因。并且，所有本征Ti02样品均为高阻态，电阻率高于10^7Ω．cm，可以排除以载流子为媒质的RKKY交换作用对系统铁磁性的影响。

英文摘要：

Intrinsic TiO2 films were prepared by RF-magnetron sputtering at different working pressures （0.2 Pa-4.0 Pa）. All as-deposited intrinsic TiO2 films show hysteresis behavior from 2 K to 340 K,andthe largest room temperature （RT） saturation magnetization （Ms） is 1.96 emu/cm^3 for the amorphous TiO2 film deposited at 2.0 Pa. From the X-ray diffraction （XRD） patterns of TiO2 films,we observe that the rutile and anatase crystal structures coexist in the TiO2 films at 0.2 Pa. With the working pressure increasing,the transformation between the rutile crystalline and anatase crystalline appears. When the working pressure is increased to 2.0 Pa,the crystalline state of TiO2 film changes from polycrystalline to amorphous. Using the high resolution transmission electron microscopy （HRTEM）, we can observe the crystalline transformation by the electron diffraction pattern and HRTEM image clearly. The transmission spectra of TiO2 films are measured by the spectrophotometer, the visible （VIS） transmittance of TiO2 films is more than 85 %, the absorption edge shifts to the longer wavelength with the amorphous transformation,and the Eg decreases to 3. 14 eV, so the increasing structural defects play an important role in the ferromagnetism of intrinsic TiO2 films. In addition, all of as-deposited samples are high-resistance state and the resistivity is higher than 10^7Ω·cm. We can rule out the effect of the carrier-mediated RKKY coupling on the system ferromagnetism.