Article

# Ultrasharp Magnetization Steps in Perovskite Manganites

[more]
Department of Physics and Materials Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
(Impact Factor: 7.51). 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.

### Full-text

Available from: John F. Mitchell, Sep 26, 2015
0 Followers
·
• Source
• "In fact, the step-like behaviors are usually observed in the systems that CO AFM states coexist with a spin-glass-like state or a short range FM order state. The origin of this phenomenon is still a matter of controversy [18], but the pictures of field-dependent CO and the jerky growth of FM fraction in a phase-separation system have been accepted [11] [12] [19] [20]. In previous studies, the martensitic-like transformation scenario has been proposed to explain the temperature-dependent properties [21] [22] [23]. "
##### Article: Dynamical behavior of step-like transition of La0.5Sr0.5Mn1−xTixO3 in a widened field sweep rate
[Hide abstract]
ABSTRACT: The magnetization behavior of Ti4+ doped perovskite manganites La0.5Sr0.5Mn1−xTixO3 (x=0.15, 0.175 and 0.2) was investigated. Experimental results show that Ti4+ dopant suppresses the antiferromagnetic charge ordering and leads to a step-like magnetization behavior below 3 K. The step-like transitions and the critical magnetic fields are strongly dependent on the Ti doping level, magnetic field sweep rate and temperature. Above 3 K, the step-like transitions transform to broad ones. In addition, under pulsed high magnetic fields with an ultrafast field sweep rate of ∼103 T/s, the sharp step-like transitions observed in the static magnetization measurements become smooth metamagnetic transition at low temperatures. This feature is correlated with the collapse of the balance between the magnetic energy and elastic energy in the phase separation system within a martensitic-like scenario.
Ceramics International 04/2015; 41(8). DOI:10.1016/j.ceramint.2015.04.040 · 2.61 Impact Factor
• ##### Article: Effect of Ni Doping on the Structural, Magnetic and Magnetocaloric Properties of Pr0.7Ca0.3Mn1−y Ni y O3 Manganites
[Hide abstract]
ABSTRACT: In this paper, we report the structural, magnetic, and magnetocaloric properties of Ni-doped Pr0.7Ca0.3Mn1−y Niy O3 (0≤y≤0.1) powder samples. Our compounds were synthesized using the solid state reaction method at high temperature. X-ray diffraction analysis using Rietveld refinement show that all our samples are single phase and crystallize in the orthorhombic structure with the Pnma space group. Magnetization measurements versus temperature in a magnetic applied field of 50 mT reveal that Ni doping leads to a paramagnetic-ferromagnetic transition with a Curie temperature increasing from 106 K for y=0.02 to 118.5 K for y=0.1. A large magnetic entropy change |ΔS M| has been observed in our doped samples with maximum values around their respective Curie temperatures T C. $|\Delta S_{\mathrm{M}}^{\mathrm{max}}|$ is found to be 2 J kg−1 K−1, 2.96 J kg−1 K−1 and 2.94 J kg−1 K−1 for y=0.02, 0.05, and 0.1, respectively, in a magnetic field change of 5 T. Large relative cooling power (RCP) value of 352.24 J kg−1 is obtained for Pr0.7Ca0.3Mn0.9Ni0.05O3 sample under 5 T.
Journal of Superconductivity and Novel Magnetism 05/2012; 26(5). DOI:10.1007/s10948-012-1830-8 · 0.91 Impact Factor
• ##### Article: Metamagnetic phase transitions induced by static and pulsed fields in (Sm0.5Gd0.5)0.55Sr0.45MnO3 ceramics
[Hide abstract]
ABSTRACT: It has been found that the magnetic susceptibility of (Sm0.5Gd0.5)0.55Sr0.45MnO3 ceramic samples in zero external magnetic field exhibits a sharp peak near the temperature of 48.5 K with a small temperature hysteresis that does not depend on the frequency of measurements and is characteristic of the phase transition to an antiferromagnetic state with a long-range charge orbital ordering, which is accompanied by an increase in the magnetic susceptibility with a decrease in the temperature. The magnetization isotherms in static and pulsed magnetic fields at temperatures below 60 K demonstrate the occurrence of an irreversible metamagnetic transition to a homogeneous ferromagnetic state with a critical transition field independent of the measurement temperature, which, apparently, is associated with the destruction of the insulating state with a long-range charge ordering. In the temperature range 60 K ≤ T ≤ 150 K, the ceramic samples undergo a magnetic-field-induced reversible phase transition to the ferromagnetic state, which is similar to the metamagnetic transition in the low-temperature phase and is caused by the destruction of local charge/orbital correlations. With an increase in the temperature, the critical transition fields increase almost linearly and the field hysteresis disappears. Near the critical fields of magnetic phase transitions, small ultra-narrow magnetization steps have been revealed in pulsed fields with a high rate of change in the magnetic field of ∼400 kOe/μs.
Physics of the Solid State 06/2012; 54(6). DOI:10.1134/S106378341206008X · 0.82 Impact Factor