nd,0.7ca,0.3xsr,xmno,3摻雜效應(yīng)及弛豫行為研究

1、華中科技大學(xué)碩士學(xué)位論文NdCaSrMnO摻雜效應(yīng)及弛豫行為研究姓名：董波申請(qǐng)學(xué)位級(jí)別：碩士專業(yè)：材料物理與化學(xué)指導(dǎo)教師：夏正才;袁松柳20060428IIAbstract Electrical transport and magnetic properties of La0.7Ca0.3-xSrxMnO3 and Nd0.7Ca0.3-ySryMnO3 systerm have been investigated. Ex

2、perimental results show that the two manganites with different A-site ion have obviously different electrical transport properties, which can not be interpreted only on the consideration of the average ionic radius . To

3、gether with the different magnetic moments of the two A-site ions, the different electrical transport between the La3+ and Nd3+ based manganites are discussed , in which the inhomogeneity related to magnetic sublattices

4、of A-site ion has an important effect on the electrical transport properties of manganites. In this thesis, the main investigation including: 1. Introduced the research history and the fact application of the magnetoresi

5、stance materials. We have summarized the crystal structure, electron structure, magnetic structure, electrical transport and magnetic properties of perovskite manganites, and then described some theoretical work about t

6、hese materials. 2. We introduced the mainly preparation procedures for perovskite manganites, and produced the La0.7Ca0.3-xSrxMnO3 and Nd0.7Ca0.3-ySryMnO3 systerm materials by the solid-state reaction and the sol-gel me

7、thod .The electrical transport and magnetic properties were measured in liquid nitrogen measurement system and commercial Physical Property Measurement System (Quantum Design PPMS). 3. Prepared the La0.7Ca0.3-xSrxMnO3 s

8、ysterm materials by the solid-state reaction ,and measured the electrical and magnetic transport properties . 4.In the Nd0.7Ca0.3-ySryMnO3 systerm ,experimental results showed that the occupation of A sites with ions o

9、f significantly different radii was expected to enhance the microstructure inhomogeneity that would play an important role in some processes, such as the spin-lattice and charge-lattice couplings , which was argued to be