Superconductivity in Fluorine-Arsenide Sr1-xNdxFeAsF

2011 ◽  
Vol 170 ◽  
pp. 87-91 ◽  
Author(s):  
Ryosuke Suganuma ◽  
Tadataka Watanabe ◽  
Kouichi Takase ◽  
Yoshiki Takano
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Weak Ferromagnetism ◽  
The Other ◽  
Superconducting Transition ◽  
Metallic Conductivity ◽  
Electrical And Magnetic Properties ◽  
New Family ◽  
Fe Impurity

We have successfully prepared the new family of fluoride-arsenide Sr1-xNdxFeAsF (0 ≤ x ≤ 0.5), and investigated the electrical and magnetic properties. Sr1-xNdxFeAsF with x = 0.4 and 0.5 show superconductivity, and their superconducting transition temperatures are 32 and 49 K, respectively. The superconducting volume fractions of Sr0.6Nd0.4FeAsF and Sr0.5Nd0.5FeAsF are ~11 and ~ 17 %, respectively. On the other hand, the sample of Sr1-xNdxFeAsF (0 ≤ x ≤ 0.35) is not superconducting but shows a metallic conductivity. All compounds show a weak ferromagnetism with the Curie temperature of above room temperature. The origin of the ferromagnetism may be due to the tiny Fe impurity.

scholarly journals The Peter Day Series of Magnetic (Super)Conductors

2021 ◽  
Vol 7 (7) ◽  
pp. 93
Author(s):  
Samia Benmansour ◽  
Carlos J. Gómez-García
Keyword(s):  
Magnetic Properties ◽  
Electrical Properties ◽  
Metal Complexes ◽  
Long Range ◽  
Magnetic Ordering ◽  
Metallic Conductivity ◽  
Electrical And Magnetic Properties ◽  
Super Conducting ◽  
Paramagnetic Metals

Here, we review the different series of (super)conducting and magnetic radical salts prepared with organic donors of the tetrathiafulvalene (TTF) family and oxalato-based metal complexes (ox = oxalate = C2O42−). Although most of these radical salts have been prepared with the donor bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF = ET), we also include all the salts prepared with other TTF-type donors such as tetrathiafulvalene (TTF), tetramethyl-tetrathiafulvalene (TM-TTF), bis(ethylenediseleno)tetrathiafulvalene (BEST), bis(ethylenedithio)tetraselenafulvalene (BETS) and 4,5bis((2S)-2-hydroxypropylthio)-4’,5’-(ethylenedithio)tetrathiafulvalene (DMPET). Most of the oxalate-based complexes are monomers of the type [MIII(C2O4)3]3−, [Ge(C2O4)3]2− or [Cu(C2O4)2]2−, but we also include the reported salts with [Fe2(C2O4)5]4− dimers, [MII(H2O)2[MIII(C2O4)3]2]4− trimers and homo- or heterometallic extended 2D layers such as [MIIMIII(C2O4)3]− and [MII2(C2O4)3]2−. We will present the different structural families and their magnetic properties (such as diamagnetism, paramagnetism, antiferromagnetism, ferromagnetism and even long-range magnetic ordering) that coexist with interesting electrical properties (such as semiconductivity, metallic conductivity and even superconductivity). We will focus on the electrical and magnetic properties of the so-called Day series formulated as β”-(BEDT-TTF)4[A+MIII(C2O4)3]·G, which represents the largest family of paramagnetic metals and superconductors reported to date, with more than fifty reported examples.

Martensitic Transformation and Mechanical Properties of Fe-Doped Ni54Mn21Ga25 Alloys

2011 ◽  
Vol 687 ◽  
pp. 500-504
Author(s):  
S. X. Xue ◽  
S.S. Feng ◽  
P. Y. Cai ◽  
Q T Li ◽  
H. B. Wang
Keyword(s):  
Magnetic Field ◽  
Mechanical Properties ◽  
Magnetic Properties ◽  
Martensitic Transformation ◽  
Curie Temperature ◽  
Directional Solidification ◽  
Transformation Temperature ◽  
Room Temperature ◽  
Martensitic Transformation Temperature ◽  
Polycrystalline Alloys

Ni54Mn21-xFexGa25（x=0,1,3,5,7,9）polycrystalline alloys were prepared by the technique of directional solidification and the effect of substituting Fe for Mn on the martensitic transformation and mechanical properties of the alloys was analyzed. It was found that the Curie temperature increased with increasing substitution while the martensitic transformation temperature decreased. The Fe-doped Ni54Mn21Ga25 alloys exhibit excellent magnetic properties at room temperature; the typical Ni54Mn20Fe1Ga25 alloy shows a large magnetic-induced-strain of -1040 ppm at a magnetic field of 4000 Oe.

Structural and magnetic properties of nitrided finemet-type ribbons

2000 ◽  
Vol 77 (9) ◽  
pp. 731-736
Author(s):  
H Atmani ◽  
S Grognet ◽  
J Teillet ◽  
K Zellama ◽  
R Zuberek
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Crystalline Phase ◽  
Room Temperature ◽  
Structural Parameters ◽  
Thermochemical Treatment ◽  
Specific Magnetization ◽  
Nano Structure ◽  
Magnetostriction Constant ◽  
Structural And Magnetic Properties

Nitriding thermochemical treatment under suitable parameters is used to nano-crystallize Fe73.5Cu1Nb3Si13.5B9 ribbon. This new kind of treatment leads to finer nano-structure and modifies the structural parameters of the α-Fe(Si) phase, obtained during the treatment. The magnetic properties are also improved; specific magnetization at room temperature and Curie temperature of the crystalline phase increase, and the magnetostriction constant becomes smaller. The nitrogenation seems to offer a new way to obtain nanostructured ribbons. PACS No.: 75.70

scholarly journals The effects of additive on microstructure and electrical properties of batio3 ceramics

2004 ◽  
Vol 1 (3) ◽  
pp. 89-98 ◽  
Author(s):  
Vesna Paunovic ◽  
Ljiljana Zivkovic ◽  
Ljubomir Vracar ◽  
Vojislav Mitic ◽  
Miroslav Miljkovic
Keyword(s):  
Dielectric Constant ◽  
Curie Temperature ◽  
Room Temperature ◽  
Low Frequency ◽  
Dissipation Factor ◽  
The Other ◽  
Uniform Microstructure ◽  
Average Grain Size ◽  
Solid State Sintering ◽  
Curie Temperatures

In this paper comparative investigations of microstructure and dielectric properties of BaTiO3 ceramics doped with 1.0 wt% of Nb2O5, MnCO3 and CaZrO3 have been done. BaTiO3 samples were prepared using conventional method of solid state sintering at 13000C for two hours. Two distinguish micro structural regions can be observed in sample doped with Nb2O5. The first one, with a very small grained microstructure and the other one, with a rod like grains. In MnCO3 and CaZrO3 doped ceramics the uniform microstructure is formed with average grain size about 0.5- 2?m and 3-5?m respectively. The highest value of dielectric permittivity at room temperature and the greatest change of permittivity in function of temperature were observed in MnCO3/BaTiO3. In all investigated samples dielectric constant after initially large value at low frequency attains a constant value at f = 6kHz. A dissipation factor is independent of frequency greater than 10 kHz and, depending of systems, lies in the range from 0.035 to 0.25. At temperatures above Curie temperatures, the permittivity of all investigated samples follows a Curie- Weiss law. A slight shift of Curie temperature to the lower temperatures, in respect of Curie temperature for undoped BaTiO3, was observed in all investigated samples.

scholarly journals Ferromagnetic Order in the Intermetallic Alloys laNi5-xMgx

2012 ◽  
Vol 29 (1) ◽  
pp. 50
Author(s):  
D.N Ba ◽  
L.T Tai ◽  
N.T Trung ◽  
N.T Huy
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Chemical Doping ◽  
Intermetallic Alloys ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ferromagnetic Order ◽  
Diffraction Patterns

The influences of the substitution of Ni with Mg on crystallographic and magnetic properties of the intermetallic alloys LaNi5-xMgx (x ≤ 0.4) were investigated. The X-ray diffraction patterns showed that all samples were of single phase, and the lattice parameters, a and c, decreased slightly upon chemical doping. LaNi5 is well known as an exchange-enhanced Pauli paramagnet. Interestingly, in LaNi5-xMgx, the ferromagnetic order existed even with a small amount of dopants; the Curie temperature reached the value of room temperature for x = 0.2, and enhanced with increasing x.

Magnetite thin films grown on different flexible polymer substrates at room temperature: Role of antiphase boundaries in electrical and magnetic properties

2020 ◽  
Vol 846 ◽  
pp. 156368
Author(s):  
Mohammad Shahnawaze Ansari ◽  
Mohd Hafiz Dzarfan Othman ◽  
Mohammad Omaish Ansari ◽  
Sana Ansari ◽  
Huda Abdullah ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Room Temperature ◽  
Antiphase Boundaries ◽  
Polymer Substrates ◽  
Electrical And Magnetic Properties ◽  
Flexible Polymer

Magnetoresistance, temporal evolution, and relaxation of the electrical resistivity in the re-entrant semiconducting La0.80Ba0.20CoO3 perovskite

1999 ◽  
Vol 14 (6) ◽  
pp. 2533-2539 ◽  
Author(s):  
R. D. Sánchez ◽  
J. Mira ◽  
J. Rivas ◽  
M. P. Breijo ◽  
M. A. Señarís-Rodríguez
Keyword(s):  
Magnetic Properties ◽  
Electrical Resistivity ◽  
Temporal Evolution ◽  
The Other ◽  
Inhomogeneous System ◽  
Metal Insulator ◽  
Relaxation Effects ◽  
Electrical And Magnetic Properties ◽  
Semiconducting Behavior ◽  
Insulator Sequence

We report here a study on the electrical and magnetic properties of La1−xBaxCoO3 in the re-entrant semiconducting region (x = 0.20). We find that in this material: (i) the insulator-metal-insulator sequence is unstable and evolves toward a purely semiconducting behavior; the initial r versus T curve can be reinstated upon appropriate annealing treatments; (ii) there are relaxation effects that can be seen by changing the polarity of the electrodes; (iii) there is a negative magnetoresistance Δρ/ρ ∼ 2–3%, for a field as low as 9 kOe, especially at the metal-insulating transition temperatures; and (iv) there are important fluctuations in the electrical resistivity. Taking into account these experimental observations, we can interpret this material as an inhomogeneous system where two thermodynamic phases, one semiconducting and the other metallic and ferromagnetic, coexist, although they are crystallographically indistinguishable.

Novel Room-temperature Ferromagnetic Semiconductors Pb1-x-yCaxCryTe

2009 ◽  
Vol 1183 ◽  
Author(s):  
Evgeny P. Skipetrov ◽  
Elena A. Zvereva ◽  
Nikolay A. Pichugin ◽  
Alexey E. Primenko ◽  
Evgeny I. Slyn'ko ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Room Temperature ◽  
Diluted Magnetic Semiconductors ◽  
Magnetic Semiconductors ◽  
Impurity Level ◽  
Ferromagnetic Semiconductors ◽  
Magnetization Curves ◽  
Diluted Magnetic ◽  
Ferromagnetic Ordering

Abstract The galvanomagnetic and magnetic properties of novel diluted magnetic semiconductors Pb1-x-yCaxCryTe (x=0.06-0.20, y=0.003-0.045) have been investigated. Temperature dependencies of the resistivity and the Hall coefficient have a metallic character indicating the pinning of Fermi level by the chromium impurity level on the background of the conduction band states. Magnetization curves display a clear hysteresis loop over the whole temperature range investigated. The Curie temperature, determined from the temperature dependencies of magnetization, achieves 345 K. Possible mechanisms of ferromagnetic ordering were discussed.

A STUDY ON MAGNETIC PROPERTIES OF Cu-DOPED GaN

2011 ◽  
Vol 25 (17) ◽  
pp. 1457-1472 ◽  
Author(s):  
LI-BIN SHI ◽  
HONG-KUAN YUAN
Keyword(s):  
Magnetic Properties ◽  
Curie Temperature ◽  
Exchange Coupling ◽  
Density Functional ◽  
Coupling Model ◽  
Weak Ferromagnetism ◽  
First Principle ◽  
Theoretical Understanding ◽  
Functional Theory ◽  
Carbon Impurities

Using the first principle method based on density functional theory (DFT), we have studied the magnetic properties in Cu -doped GaN . The result shows that Cu in GaN exhibits spontaneous spin polarization. The energies of ferromagnetism (FM) and antiferromagnetism (AFM) coupling are calculated for eleven different configurations. It is found that Cu -doped GaN has a FM ground state. It is not found that Cu atoms have a clear clustering tendency. Origin of FM properties is also explained by energy level coupling model. In the paper, we also investigate the effect of nitrogen, gallium vacancies and carbon impurities on magnetic properties. The results show that nitrogen, gallium vacancies and carbon impurities cannot enhance FM coupling of Cu -doped GaN . In addition, exchange coupling coefficient and Curie temperature are also investigated. The Cu -doped GaN is proposed to be weak ferromagnetism according to Curie temperature and magnetic moment. The present study provides some theoretical understanding for the experiments on Cu -doped GaN .

Glass-Coated Cu-Mn-Ga Microwires Produced by Taylor-Ulitovsky Technique

2009 ◽  
Vol 152-153 ◽  
pp. 79-84 ◽  
Author(s):  
Joan Josep Suñol ◽  
L. Escoda ◽  
C. García ◽  
V.M. Prida ◽  
Victor Vega ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solid Solution ◽  
Curie Temperature ◽  
Energy Dispersive Spectroscopy ◽  
Room Temperature ◽  
Alloy Composition ◽  
The Other ◽  
X Ray Diffraction ◽  
X Ray ◽  
Low Magnetic Field

Glass-coated Cu-Mn-Ga microwires were fabricated by Taylor-Ulitovsky technique. By means of energy dispersive spectroscopy microanalysis, an average alloy composition of Cu56Ga28Mn16 was determined. The temperature dependence of magnetization measured at a low magnetic field showed the coexistence of two ferromagnetic phases. The Curie temperature of one phase is 125 K and above room temperature for the other one. X-ray diffraction at room temperature and at 100 K reflects the presence of the same three crystalline phases corresponding to the cubic B2 Cu-Mn-Ga structure as a main phase and the minor phases of fcc Cu rich solid solution with Mn and Ga and the monoclinic CuO.

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