Influence of Tb substitution for La on the structure, magnetic and magneto-transport properties of La<sub>1.2sub>Sr<sub>1.8sub>Mn<sub>2sub>O<sub>7sub>
- 作者：Min Zhou ; Hong-Ye Wu ; Hong-jin Wang ; Lin Zheng ; Jian-Jun Zhao ; Ru Xing ; Yi Lu<sup> ; sup><sup>yilu1958@163.comsup>
- 关键词：Manganite ; Magnetic property ; Magneto-resistance
- 刊名：Physica B
- 出版年：2012
- 期刊代码：53_09214526
- 类别：ph
- 出版时间：15 June, 2012
- 卷：407
- 期：12
- 页码：2219-2222
- 文件大小：315 K
摘要
The physical properties of Tb<sup>3+sup> ions substitution at A-site are investigated in the layered manganite La<sub>1.2sub>Sr<sub>1.8sub>Mn<sub>2sub>O<sub>7sub>. A series of La<sub>1.2鈭?em>xsub>Tb<sub>xsub>Sr<sub>1.8sub>Mn<sub>2sub>O<sub>7sub> (x=0, 0.05, 0.15, and 0.20) shows that doping with a Tb ion of smaller radius in La<sub>1.2sub>Sr<sub>1.8sub>Mn<sub>2sub>O<sub>7sub> caused diffraction peaks to shift to high angle. Some samples have an impure diffraction at about 30掳, but all samples form single-phase. Samples can be well indexed on a Sr<sub>3sub>Ti<sub>2sub>O7-type tetragonal structure with the space group I4/mmm. According to the M-T curves, when x鈮?.05, the series of samples shows ferromagnetism at low temperatures. With increasing temperature, they have two magnetic transitions at different temperatures. When x鈮?.15, the magnetizations dramatically decrease. The 蟻-T curves of samples show the metal-insulator transition for x=0, 0.05, and the maximum MR values in magnetic field 5 T are 74%at about 73 K and 94%at about 86 K. When x鈮?.15, the samples remain in the insulator state in the whole observed temperature range, and the maximum MR values of 86%and 69%appeared at 74 K and 42 K.