Ultrasharp magnetization steps in perovskite manganites.

Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
Physical Review Letters (Impact Factor: 7.73). 12/2002; 89(28 Pt 1):286602. DOI: 10.1103/PhysRevLett.89.286602
Source: PubMed

ABSTRACT We report a detailed study of steplike metamagnetic transitions in polycrystalline Pr0.5Ca0.5Mn0.95Co0.05O3. The steps have a sudden onset below a critical temperature, are extremely sharp (width <2x10(-4) T), and occur at critical fields which are linearly dependent on the absolute value of the cooling field in which the sample is prepared. Similar transitions are also observed at low temperature in non-Co doped manganites, including single crystal samples. These data show that the steps are an intrinsic property, qualitatively different from either previously observed higher temperature metamagnetic transitions in the manganites or metamagnetic transitions observed in other materials.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Antisite disorder is observed to have significant impact on the magnetic properties of the double perovskite Y2CoMnO6 which has been recently identified as a multiferroic. A paramagnetic-ferromagnetic phase transition occurs in this material at Tc ≈ 75 K. At 2 K, it displays a strong ferromagnetic hysteresis with a significant coercive field of Hc ≈ 15 kOe. Sharp steps are observed in the hysteresis curves recorded below 8 K. In the temperature range 2 K ≤ T ≤ 5 K, the hysteresis loops are anomalous as the virgin curve lies outside the main loop. The field-cooling conditions as well as the rate of field-sweep are found to influence the steps. Quantitative analysis of the neutron diffraction data shows that at room temperature, Y2CoMnO6 consists of 62% of monoclinic P21/n with nearly 70% antisite disorder and 38% Pnma. The bond valence sums indicate the presence of other valence states for Co and Mn which arise from disorder. We explain the origin of steps by using a model for pinning of magnetization at the antiphase boundaries created by antisite disorder. The steps in magnetization closely resemble the martensitic transformations found in intermetallics and display first-order characteristics as revealed in the Arrott's plots.
    Journal of Applied Physics 09/2014; 116(12):123907-123907-7. DOI:10.1063/1.4896399 · 2.19 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In recent years, X-ray photon correlation spectroscopy (XPCS) has emerged as one of the key probes of slow nanoscale fluctuations, applicable to a wide range of condensed matter and materials systems. This article briefly reviews the basic principles of XPCS as well as some of its recent applications, and discusses some novel approaches to XPCS analysis. It concludes with a discussion of the future impact of diffraction-limited storage rings on new types of XPCS experiments, pushing the temporal resolution to nanosecond and possibly even picosecond time scales.
    Journal of Synchrotron Radiation 09/2014; 21(Pt 5):1057-1064. DOI:10.1107/S1600577514018232 · 2.19 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Low-temperature transport properties were systemically studied for the series of (1-x) La2/3Sr1/3MnO3 + x ZrO2 (x = 0, 3%, 6%, and 9%) matrix composites under a weak applied magnetic field from 0 to 1 T. The nanoscaled nonmagnetic ZrO2 particles which are introduced as a secondary phase has been put into ferromagnetic ground state metal La2/3Sr1/3MnO3. As the density of ZrO2 nanoparticles increases, the ferromagnetic ordering of the system will enhance as well as the electric transport at low temperatures. The temperature and weak magnetic field dependences of the resistivity upturns of our samples are in good agreement with a combination of electron-electron interaction and weak localization.
    RSC Advances 11/2014; 5(3). DOI:10.1039/C4RA11513A · 3.71 Impact Factor

Full-text (2 Sources)

Available from
Jun 5, 2014