Effects of Organic Material on Magnetoresistance in Electron-doped Double Perovskite

The Curie temperature of electron-doped Sr2FeMoO6 can be optimized significantly due to the band-filling effect, but accompanying an almost absent low-field magnetoresistance (LFMR), which is unfavorable to applications in the magnetoresistive devices operated at room-temperature. Our previous works confirmed that, a remarkable enhanced LFMR was observed in Sr2FeMoO6 by modifying the grain boundary with insulating organic small molecules (glycerin, CH2OHCHOHCH2OH). However, in this work, modifying the grain boundary strength of the La0.5Sr1.5FeMoO6 with the insulating organic macromolecules (oleic acid, CH3(CH2)7CH=CH(CH2)7COOH) or small molecules (glycerin), both of them have negligible functions on the magnetoresistance behavior in La0.5Sr1.5FeMoO6. Contrary to the glycerin-modified Sr2FeMoO6, Sr2FeMoO6/oleic acid composites don’t exhibit an obviously increased magnetoresistance property. Based on the above experimental results and the related works, it is proposed that, maintaining high spin polarization of the carriers at the Fermi level and improving the tunneling process across the grain boundary by using the suitable organic materials are decisive factors for optimizing the magnetoresistance behavior in the similar electron-doped double perovskites.

Green Synthesis of Tungsten Ditelluride and the Magnetoresistance Property

As a new type of unsaturated linear magnetoresistive materials, tungsten ditelluride series material has potential applications in the fields of strong magnetic detection, information recording and magnetic storage devices. The current development concepts of “green materials”, “green chemical technology” and “environmentally friendly technology” require us to pursue the non-toxic, low-emission and non-emission in material synthesis technology. At the same time, the prepared products show excellent performance and high versatility and efficiency. According to our previous work, the study attempts to use a low-volatile amine solvent as a pretreatment raw material to synthesize a tungsten germanium-based linear magnetoresistive material by hydrothermal/solvothermal method and self-fluxing method. The obtained materials were subjected to XRD, Raman, SEM and Magnetoresistance. Experimental results show that when the mass ratio of W and Te is 1:4, the prepared material is pure phase and the sample is the layered structure. The Magnetoresistance Property points out that the maximum value is about 190 %, which appears in the condition of 10 K and 7 T. Those test projects include phase, structure and morphology characteristics, and provide technical parameters and methods for the development of green synthesis and potential applications of tungsten ditelluride series linear magnetoresistive materials.