%0 Journal Article
%T Research on a New Process of Preparation for Nano-SiO2 with High Activity and Mesopores<br>Research on a New Process of Preparation for Nano-SiO_2 with High Activity and Mesopores
%A Ruijing ZHANG
%A Ke YANG
%A Tianying XIONG
%A <br>Ruijing ZHANG
%A Ke YANG
%A Tianyng XIONG Institute of Metal Resarch
%A Chinese Academy of Sciences
%A Shenyang
%A China
%J 材料科学技术学报
%D 2004
%I 
%X With substitution of La by Tb in (La1-xTbx)0.67Sr0.33MnO3, the room temperature magnetoresistance AR/R0 drops at first, then undergoes an increase near x≈0.1, and finally drops again. The value of room temperature magnetoresistance at a field H=12 kOe for (La0.9Tb0.1)0.67Sr0.33MnO3 is -3.56%. The enhancement of the room temperature magnetoresistance induced by an appropriate Tb substitution in (La1-xTbx)0.67Sr0.33MnO3 is correlated with the shifts of the Curie temperature and metal-insulator temperature to near room temperature. The drop of the room temperature magnetoresistance at large Tb doping-contents may be due to its lower TC and TMI far from the room temperature.
%K Heat treatment
%K Ball milling
%K Mesopores
%K Nano-SiO2<br>
%U http://www.alljournals.cn/get_abstract_url.aspx?pcid=5B3AB970F71A803DEACDC0559115BFCF0A068CD97DD29835&cid=84529CA2B2E519AC&jid=324DC3CAB22330DB19158AE0A9B7BFA5&aid=CBF83D012D9CD183&yid=D0E58B75BFD8E51C&vid=A04140E723CB732E&iid=38B194292C032A66&sid=A5111BA190517959&eid=35E8A259891FB32F&journal_id=1005-0302&journal_name=材料科学技术学报&referenced_num=3&reference_num=12