离子取代对La2CuO4的结构和磁学性质的影响

摘要

La2CuO4的结构中因存在键角为180°的…Cu—O—Cu—O—Cu…链而表现出反铁磁性.Zn2+或Mg2+取代Cu2+后就破坏了这种长程有序，使Cu2+的有效磁矩升高，并且在77～300K温区内观察不到Néel态.La2Cu1-xNixO4没有电子自旋共振(ESR)响应，也观察不到其Néel态.La2Cu1-xMx O4(M=Zn2+,Mg2+)有ESR响应，这种响应很可能是由拉长的CuO6八面体产生的.采用常规的物理方法如X-射线粉末衍射(XRD)和电子自旋共振等对样品进行了表征.%La2CuO4 is antiferromagnetic due to the existence of…Cu—O—Cu—O—Cu… chainlike structure whose bond angle is 180°.The substitution of Cu2+by Zn2+or Mg2+ frustrates this long-range ordering and raises the effective magnetic moment of Cu2+,and the Néel state can not be observed in a temperature range of 77～300K.La2Cu1-xNixO4 is ESR-silent and its Néel state can not be observed either.La2Cu1-xMxO4(M=Zn2+, Mg2+)give ESR signals which are supposed to be induced by the elongated CuO6 octahedron. Samples were characterized by conventional physical techniques such as X-ray diffraction(XRD),electron spin resonance(ESR)and so on.