scholarly journals Influence of thermal treatment on the ionic valence and the magnetic structure of perovskite manganites La0.95Sr0.05MnO3

2016 ◽  
Vol 65 (2) ◽  
pp. 027501
Author(s):  
Wu Li-Qian ◽  
Qi Wei-Hua ◽  
Li Yu-Chen ◽  
Li Shi-Qiang ◽  
Li Zhuang-Zhi ◽  
...  
Keyword(s):  
Thermal Treatment ◽  
Magnetic Structure ◽  
Perovskite Manganites ◽  
Ionic Valence

Transition Insulator-Metal and Antiferromagnetic-Paramagnetic Cu Doped in La0.47Ca0.53MnO3

2015 ◽  
Vol 1123 ◽  
pp. 73-77 ◽  
Author(s):  
Yohanes Edi Gunanto ◽  
K. Sinaga ◽  
B. Kurniawan ◽  
S. Poertadji ◽  
H. Tanaka ◽  
...  
Keyword(s):  
High Resolution ◽  
Low Temperature ◽  
Magnetic Structure ◽  
Room Temperature ◽  
Paramagnetic Phase ◽  
Perovskite Manganites ◽  
Antiferromagnetic Phase ◽  
Temperature Transition ◽  
Cu Doping ◽  
Metal State

The study of the perovskite manganites La0.47Ca0.53Mn1-xCuxO3 with x = 0, 0.06, 0.09, and 0.13 has been done. The magnetic structure was determined using high-resolution neutron scattering at room temperature and low temperature. All samples were paramagnetic at room temperature and antiferromagnetic at low temperature. Using the SQUID Quantum Design, the samples showed that the doping of the insulating antiferromagnetic phase La0.47Ca0.53MnO3 with Cu doping resulted in the temperature transition from an insulator to metal state, and an antiferromagnetic to paramagnetic phase. The temperature transition from an insulator to metal state ranged from 23 to 100 K and from 200 to 230 K for the transition from an antiferromagnetic to paramagnetic phase.

Magnetic Phase Diagram in Layered Perovskite Manganite La2-2xSr1+2xMn2O7 (0.313≤x≤0.350)

2006 ◽  
Vol 512 ◽  
pp. 183-188 ◽  
Author(s):  
Takeshi Murata ◽  
Tomoyuki Terai ◽  
Takashi Fukuda ◽  
Tomoyuki Kakeshita
Keyword(s):  
Phase Diagram ◽  
Magnetic Structure ◽  
Easy Axis ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
The Other ◽  
Layered Perovskite ◽  
Perovskite Manganites ◽  
Perovskite Manganite ◽  
Magnetic Structures

We have measured the magnetization as a function of temperature and magnetic field in layered perovskite manganites of La2-2xSr1+2xMn2O7 single crystals (x=0.313, 0.315, 0.320, 0.350) in order to know their magnetic structures. All the present manganites exhibit magnetic transitions from ferromagnetic to paramagnetic at 76K, 107K, 120K and 125K for x=0.313, 0.315, 0.320 and 0.350, respectively. For x=0.350 and 0.320, the magnetic structure is a planar ferromagnetism whose easy axis is in the ab-plane at all temperatures below the Curie temperature. On the other hand, for x=0.315 and 0.313, the magnetic structure is an uniaxial ferromagnetism whose easy axis is along the c-axis below 85K and 66K, respectively, and a planar ferromagnetism above the temperature. From the results described above, we made the detailed magnetic phase diagram of layered perovskite manganite La2-2xSr1+2xMn2O7 (0.313≤x≤0.350).

Magnetism and CMR in Electron Doped Perovskite and Layered Manganites

1999 ◽  
Vol 602 ◽  
Author(s):  
A. Maignan ◽  
C. Martin ◽  
M. Hervieu ◽  
B. Raveau
Keyword(s):  
Phase Diagrams ◽  
Magnetic Structure ◽  
Magnetic Phase ◽  
Structure Study ◽  
Charge Ordering ◽  
Perovskite Manganites ◽  
Doped Manganites ◽  
Magnetic Phase Diagrams

AbstractFrom the magnetic phase diagrams established for Ln1−xAExMnO3 manganites with x>0.5, it is shown that the magnetoresistance is only obtained for compositions of smallest average Asite cations <rA>. The magnetic structure study reveals that the small <rA> favors the coexistence of ferromagnetism with G-type antiferromagnetism. It is also shown that ferromagnetism can be induced in the Ln2−xAExMnO4 type electron doped manganites by using compositions with small Ln and AE cations and x values close to 1.90. Finally, manganse site doping by Cr, Co, Ni can be used to weaken the charge-ordering of the Mn4+ rich perovskite manganites (0.5<x≤0.8) and thus to induce CMR properties.

Pollutant Identification by Selected Area Electron Diffraction

1974 ◽  
Vol 32 ◽  
pp. 532-533
Author(s):  
R. E. Ferrell ◽  
G. G. Paulson ◽  
C. W. Walker
Keyword(s):  
Thermal Treatment ◽  
Electron Diffraction ◽  
Sample Preparation ◽  
Crystal Structures ◽  
Water Samples ◽  
Environmental Samples ◽  
Short Review ◽  
Selected Area Electron Diffraction ◽  
Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

Development of Crystallinity in Turbostratic Boron Nitride Derived from Polymeric Precursors

1991 ◽  
Vol 49 ◽  
pp. 954-955
Author(s):  
X. Qiu ◽  
A. K. Datye ◽  
T. T. Borek ◽  
R. T. Paine
Keyword(s):  
Thermal Treatment ◽  
Boron Nitride ◽  
Diffraction Pattern ◽  
Polymeric Precursors ◽  
Polymer Precursors ◽  
Diffuse Ring

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.

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