Phase diagram of the La1-xCaxMnO3 compound (0.5 <= x <= 0.9)

Article

关键词: FERROMAGNETIC PHASE;    WIGNER-CRYSTAL;    BI-STRIPE;    CHARGE;    TEMPERATURE;    DIFFRACTION;    MANGANITES;    TRANSPORT;    X=0.25;    FIELD;   

DOI  :  10.1103/PhysRevB.68.134414

来源: SCIE

【 摘 要 】

We have studied the phase diagram of La1-xCaxMnO3 for 0.5less than or equal toxless than or equal to0.9 using neutron powder diffraction and magnetization measurements. At 300 K all samples are paramagnetic and single phase with crystallographic symmetry Pnma. As the temperature is reduced a structural transition is observed which is to a charge-ordered state only for certain x. On further cooling the material passes to an antiferromagnetic ground state with Neel temperature T-N that depends on x. For 0.8less than or equal toxless than or equal to0.9 the structural transformation occurs at the same temperature as the magnetic transition. Overall, the neutron-diffraction patterns were explained by considering four phase boundaries for which La1-xCaxMnO3 forms a distinct phase: the charge-ordered phases at x=0.5 and x=2/3, the monoclinic and C-type magnetic structure at x=0.80-0.85, and the G-type magnetic structure at x=1. Between these phase boundaries the magnetic reflections suggest the existence of mixed compounds containing both phases of the adjacent phase boundaries.

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