CrO_(2)-TiO_(2) composites are synthesized by using a high temperature and high pressure method using CrO_(3) and H_(2)TiO_(3) as precursors.The composites consist of large rod-like CrO_(2) crystals separated by small...CrO_(2)-TiO_(2) composites are synthesized by using a high temperature and high pressure method using CrO_(3) and H_(2)TiO_(3) as precursors.The composites consist of large rod-like CrO_(2) crystals separated by small TiO_(2) grains.The CrO_(2) in the composites is very pure and its saturation magnetization is very close to the theoretical value(i.e.,2μ_(B) per formula unit).The composites exhibit a large negative magnetoresistance(MR)at 5 K.The MR in CrO_(2)-TiO_(2) composites is mainly attributed to spin-polarized tunneling between CrO_(2) crystals.The conductivity of the composites is best described by a fluctuation-induced tunneling model below 230 K.展开更多
The submicron chromium dioxide（CrO2） thin film was fabricated on a poly-crystal titania（TiO2） film using Si wafers as substrates by atmospheric pressure chemical vapor deposition（CVD） method. X-Ray diffraction p...The submicron chromium dioxide（CrO2） thin film was fabricated on a poly-crystal titania（TiO2） film using Si wafers as substrates by atmospheric pressure chemical vapor deposition（CVD） method. X-Ray diffraction patterns show that the CrO2 films were pure rutile structure. Scanning electron microscopy（SEM） images indicate that the CrO2 films consisted of submicron grains with a grain size of 250--750 rim. The magnetic researches reveal that the magnetic easy axis is parallel to the films, and at room temperature, the CrO2 films show linear magnetoresistance.展开更多
基金Supported by the National Natural Science Foundation of China under Grant No 50972048the Program for New Century Excellent Talents in University.
文摘CrO_(2)-TiO_(2) composites are synthesized by using a high temperature and high pressure method using CrO_(3) and H_(2)TiO_(3) as precursors.The composites consist of large rod-like CrO_(2) crystals separated by small TiO_(2) grains.The CrO_(2) in the composites is very pure and its saturation magnetization is very close to the theoretical value(i.e.,2μ_(B) per formula unit).The composites exhibit a large negative magnetoresistance(MR)at 5 K.The MR in CrO_(2)-TiO_(2) composites is mainly attributed to spin-polarized tunneling between CrO_(2) crystals.The conductivity of the composites is best described by a fluctuation-induced tunneling model below 230 K.
基金Supported by the the National Natural Science Foundation of China（Nos.50972048, 61201007）, the Fundamental Research Fund for the Central Universities of China（No.ZYGX2011 J022）, the Youth Fund of Education Department of Jiangxi Province of China（No.GJJ12575） and the Open Project of State Key Laboratory of Superhard Materials（Jilin University） of China （No.201213）.
文摘The submicron chromium dioxide（CrO2） thin film was fabricated on a poly-crystal titania（TiO2） film using Si wafers as substrates by atmospheric pressure chemical vapor deposition（CVD） method. X-Ray diffraction patterns show that the CrO2 films were pure rutile structure. Scanning electron microscopy（SEM） images indicate that the CrO2 films consisted of submicron grains with a grain size of 250--750 rim. The magnetic researches reveal that the magnetic easy axis is parallel to the films, and at room temperature, the CrO2 films show linear magnetoresistance.
