本文利用溶胶凝胶法，成功制备了名义成分为La0．75 Sr0．25 M n1－x O3（x ＝0．00，0．03，0．05，0．08，0．10，0．13，0．15，0．17）的含有B位空位的钙钛矿样品，最高煅烧温度为1073 K ．利用软件X＇Pert HighScore Plus对样品的XRD图谱进行分析，当 x ≤0．08的样品为钙钛矿单相，其余样品含有次相镧的氧化物，说明B位空位存在最大值，0．08＜ zm ＜0．10；磁性测量结果说明B位空位含量的增加一方面增加了M n4＋含量，另外一方面阻碍了M n3＋－O 2－－ M n4＋双交换作用．%We had prepared the no m inal co m position La0 .75 Sr0 .25 M n1-x O3 ( x = 0 .00 ,0 .03 ,0 .05 ,0 .08 ,0 .10 , 0 .13 ,0 .15 ,0 .17) with the highest calined temperature 1 073 K by Sol Gel method .Using X'Pert HighScore Plus software ,the XRD patterns indicates the samples have a single phase when x ≤ 0 .08 ,and a second phase La2O3 when 0 .10 ≤ x ≤ 0 .17 ,which shows that there is a maximum value of vacancy content at the B sites ,0 .08 < zm <0 .10 .The magnetic properties performed by PPMS indicates that the increase of vacancy increase the content of M n4+ at the B sites ,and destroy the path of M n3+ -O2- - M n4+ and decrease the double exchange pole .
展开▼
