Charge Ordering and Ferromagnetic Transition in Single-Crystal Eu4As3

2003 ◽  
Vol 72 (12) ◽  
pp. 3174-3181 ◽  
Author(s):  
Akira Ochiai ◽  
Yuji Shima ◽  
Makoto Shirakawa
Keyword(s):  
Single Crystal ◽  
Charge Ordering ◽  
Ferromagnetic Transition

CRYSTALLINE STRUCTURE AND PHYSICAL PROPERTIES OF UCo2Al3

2004 ◽  
Vol 18 (30) ◽  
pp. 3905-3914
Author(s):  
E. VERDÍN ◽  
R. ESCUDERO
Keyword(s):  
Intermetallic Compound ◽  
Physical Properties ◽  
Single Crystal ◽  
Intermetallic Compounds ◽  
Heavy Fermion ◽  
Ferromagnetic Transition ◽  
Crystallographic Characteristics ◽  
Heavy Fermion Behavior ◽  
Small Single Crystal ◽  
Weak Ferromagnetic

Some intermetallic compounds which contain uranium or cerium present heavy fermion characteristics. Take, for example, in the UM 2 Al 3 ( M = Pd , Ni ) family, superconductivity and magnetism coexist and present heavy fermion behavior. This work presents the crystallographic characteristics and physical properties of a new compound of this family; the intermetallic compound UCo 2 Al 3. Our initial crystallographic studies performed in a small single crystal show that the structure is hexagonal and similar to the UNi 2 Al 3 and UPd 2 Al 3 parent compounds. The space group is P6/mmm with a=5.125 Å and c=4.167 Å crystalline parameters. Measurements of resistivity and magnetization performed on the single crystal reveal that the compound is not superconducting when measured at about 1.8 K. The compound is highly anisotropic and features related to Kondo-like behavior are observed. A weak ferromagnetic transition is observed at a temperature of about 20 K.

Charge ordering and the related structural phase transition in single-crystal(Bi0.24Ca0.76)MnO3

1999 ◽  
Vol 59 (18) ◽  
pp. 11687-11692 ◽  
Author(s):  
Y. Su ◽  
C-H. Du ◽  
P. D. Hatton ◽  
S. P. Collins ◽  
S-W. Cheong
Keyword(s):  
Phase Transition ◽  
Single Crystal ◽  
Structural Phase Transition ◽  
Structural Phase ◽  
Charge Ordering

X-ray diffraction single-crystal structure characterization of iron ludwigite from room temperature to 15 K

2006 ◽  
Vol 39 (1) ◽  
pp. 42-45 ◽  
Author(s):  
M. Mir ◽  
Jan Janczak ◽  
Y. P. Mascarenhas
Keyword(s):  
Single Crystal ◽  
Room Temperature ◽  
Structural Characteristics ◽  
Density Wave ◽  
Charge Ordering ◽  
Structure Characterization ◽  
Dimensional Structure ◽  
X Ray ◽  
Extra Electron ◽  
A Charge

Iron ludwigite exhibits a superstructure between 283 and 144 K. Anomalies in its transport properties are due to a structural transition related to a charge-ordering phenomenon in the low-dimensional structure. This ordering produces a commensurate transversal charge density wave in the system. To understand these structural characteristics, an X-ray single-crystal diffraction study has been performed at 300 and 15 K. No changes were found in the crystalline structure, except for contraction of the cell volume. The bond-valence sum for each cation shows that at room temperature each Fe4—Fe2—Fe4 triad is composed of three Fe3+ions with one extra electron per triad, and at 15 K in each Fe4a—Fe2—Fe4btriad the extra electron is accommodated in the Fe4a—Fe2 pair of each triad.

scholarly journals Magnetic and Transport Studies of Strongly Correlated Perovskite Ceramics

2021 ◽  
Author(s):  
◽  
Erwan Hemery
Keyword(s):  
Transition Temperature ◽  
Thermoelectric Power ◽  
Transition Metal Oxides ◽  
Magnetic Measurements ◽  
Oxygen Deficiency ◽  
Double Perovskite ◽  
Charge Ordering ◽  
Power Measurement ◽  
Ferromagnetic Transition ◽  
Strongly Correlated

<p>This thesis describes the results from an experimental study of the magnetic and transport properties of two strongly correlated transition metal oxides. The firstmaterial under study is the ferromagnetic half-metal double perovskite, Sr2FeMoO6, in which we have made isoelectronic (Ba2+) and electronic (La3+) substitutions onto the strontium site. Magnetoresistance measurements on Sr2-xBaxFeMoO6 revealed that the low temperature magnetoresistance is dominated by inter-grain transport while the intra-grain contribution is evident when the temperature is close to the ferromagnetic transition temperature. Transport measurements on Sr2-xLaxFeMoO6 clearly showed that the doping dependence of the thermoelectric power is surprisingly similar to the one observed in the superconducting cuprates. In addition, it was found that the electronic doping leads to an increase in the ferromagnetic transition temperature, which supports the band filling model. Substitution on the Fe site was also investigated by partially replacing Fe with the non-magnetic aluminium element (Sr2Fe1-xAlxMoO6). It was found from thermoelectric power measurement that the Fe electronic state is below3+,which is inconsistentwith theoretical models but is in good agreement with Mossbauer measurements. In addition, magnetic measurements showed that the reduction in the ferromagnetic ordering temperature could be explained in terms of a 3D percolation model. The second compound is the oxygen deficient strontium iron oxide SrFeO3-delta . The temperature dependence of the thermoelectric power was measured in this compound for the first time and shown to be reminiscent of the charge-ordering Verwey transition observed in Fe3O4. Magnetic measurements show an increase of a weak ferromagnetic signal versus the oxygen deficiency that could originate from a Dzyaloshinsky-Moriya interaction in the distorted FeO6 octahedra. Finally, we observed a large magnetoresistance near room temperature for compounds close to the orthorhombic SrFeO2.75 phase.</p>

scholarly journals Magnetoresistive study of the antiferromagnetic–weak ferromagnetic transition in single-crystal La2CuO4+δ

2004 ◽  
Vol 30 (5) ◽  
pp. 411-416 ◽  
Author(s):  
B. I. Belevtsev ◽  
N. V. Dalakova ◽  
V. N. Savitsky ◽  
A. S. Panfilov ◽  
I. S. Braude ◽  
...  
Keyword(s):  
Single Crystal ◽  
Ferromagnetic Transition ◽  
Weak Ferromagnetic

Antiferromagnetic resonance in charge ordering state of Pr0.5Ca0.5MnO3−δ single crystal

2001 ◽  
Vol 226-230 ◽  
pp. 854-856 ◽  
Author(s):  
S Kawamata ◽  
S Noguchi ◽  
K Okuda ◽  
H Nojiri ◽  
M Motokawa
Keyword(s):  
Single Crystal ◽  
Charge Ordering ◽  
Antiferromagnetic Resonance

Field-induced first-order ferromagnetic transition in (La0.8Eu0.2)4/3Sr5/3Mn2O7 single crystal

2019 ◽  
Vol 18 (1) ◽  
pp. 55-62 ◽  
Author(s):  
Ru Xing ◽  
Wen-Qing Wang ◽  
Yi Lu ◽  
Jian-Jun Zhao
Keyword(s):  
Single Crystal ◽  
Ferromagnetic Transition ◽  
First Order
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