The Synthesis And Characterization Of A Novel 1111-type Diluted Magnetic Semiconductor(La_1-xSr_x)(Zn_1-xMn_x)SbO

Diluted magnetic semiconductors(DMS)that combine the properties of both spin and charge degrees of freedom,which have potential applications in the field of spintronic devices.In the 1990s,due to the breakthrough of low-temperature molecular beam epitaxy technology,scien-tists successfully synthesized ?-? DMS(Ga,Mn)As,and developed some spintronics devices accordingly.However,the maximum Curie temperature of(Ga,Mn)As is only 200 K,which is still below room temperature that is required for practical applications.Searching for diluted magnetic semiconductors with higher Curie temperature and the exploration of their magnetism is still one of the focuses at present.In recent years,developed from iron-based superconductors,a series of novel magnetic semiconductors have been reported.These new DMSs have the advantages of decoupled charge and spin doping,and each concentration can be precisely controlled.The research on diluted magnetic semiconductors in this paper mainly focuses on the following three aspects:(1)The synthesis and characterization of a novel diluted magnetic semiconductor.By the substitution of Sr and Mn,carrier and local magnetic moment are introduced respectively in LaZnSbO.The ferromagnetic ordered phase can be observed in the samples with various dop-ing concentrations.When the doping concentration x=0.1,the Curie temperature is as high as 27.1 K,and the isothermal magnetization curve measured at the temperature of 2 K indi-cates that its coerce force is 5000 Oe.(La1-xSrx)(Zn1-xMnx)SbO has the same crystal structure as LaMnAsO,the "1111" type anti-ferromagnet,and LaFeAsO,the parent compound of the"1111" type iron-based superconductor,with little difference in lattice parameters.It provides a possible material choice for the preparation of multifunctional heterogeneous junction devices in future.(2)The influence of chemical pressure on a lattice structure and physical properties of di-luted magnetic semiconductor(La0.9Ba0.1)(Zn0.9Mn0.1)AsO was investigated by doping Sb in As sites.Since the radius of Sb ions is greater than that of As ions,the lattice expands after dop-ing,namely,negative chemical pressure is introduced into(La0.9Ba0.1)(Zn0.9Mn0.1)O(As1-xSbx)system.With the increasing of Sb doping amount,the a axis and c axis of the cell increase posi-tively,which proves the successful introduction of negative chemical pressure.The results pro-vide a possible experimental basis for future research on the magnetic source of diluted magnetic semiconductor.(3)By doping carriers and local magnetic moment in several semiconductors,whether di-luted magnetic semiconductors are succeeded have been explored in this paper.Unfortunately,the magnetism in these dilute magnetic semiconductors did not show up as expected.We recorded the research process and experimental results in the last chapter to provide a reference for sub-sequent researchers.