Study On Synthesis And Performance Of The Manganese Droped CaB₆and CaB₄Single Crystal

This research is aim to synthesis the alloy of Ca-Mn in the condition of hightemperature and high pressure. We finished the analyses of X-ray diffraction andenergy dispersive spectrometers of the alloy of Ca-Mn in order to get the right dopingratio. In the conditions of high temperature and high pressure, two kinds of the Mndoped Ca-B single crystals were synthesized by controlling the pressure, respectively,using the alloy of Ca-Mn and B as the raw materials. Later we study the X-raydiffraction and energy dispersive spectrometers of the Mn doped CaB₆and CaB₄crystals in order to analysis the composition and structure of the Mn doped samples.The resistivity and magnetic properties of Mn doped CaB_x（x=4,6） are measured byPPMS.The experiment is divided into three parts: The first we mixed the preloading Capiece （purity of98.5%） and Mn （99.99%） powder with different proportion. Then theCa-Mn alloys were synthesized in the pressure of2GPa and4GPa with thetemperature of1400℃, then we analysised the composition of sampers to get theright doping ratio. The second part is that we synthesized the Mn doped of CaB₆byusing B powder （purity of99.99%） and Ca-Mn alloy pieces at the experimentalcondition of1GPa and1000℃-1200℃. The last part is that we synthesized the Mndoped of CaB₄single crystals by using B powder （purity of99.99%） and Ca-Mn alloypieces. The experimental condition is the pressure of2-3GPa and the temperature of1000℃-1200℃.The detections of electrical properties show that the Mn dropped CaB₆compoundis a semiconductor. The Mn droped CaB₄crystals have a metallic conductivebehavior.And the Mn doped CaB₆and CaB₄crystals all have the weakferromagnetism through the detections of magnetism.