Magnetic Properties and Structural Transitions in (MnCo)1-xGe

2009 ◽  
Vol 152-153 ◽  
pp. 489-492 ◽  
Author(s):  
P.E. Markin ◽  
N.V. Mushnikov
Keyword(s):  
Magnetic Field ◽  
Structural Transition ◽  
Magnetic Phase ◽  
Hexagonal Phase ◽  
Magnetic Transition ◽  
Entropy Change ◽  
Paramagnetic State ◽  
X Ray Diffraction ◽  
X Ray ◽  
Isothermal Regime

The magnetic and X-ray diffraction measurements of the ferromagnetic compounds (MnCo)1-xGe have been performed for the concentration range 0 ≤ x ≤ 0.05. The structural and magnetic phase diagrams have been obtained. Compositions for which the magnetic transition from ferromagnetic to paramagnetic state coincides with the structural transition from an orthorhombic to a hexagonal phase have been determined to be 0.015 ≤ x ≤ 0.025. It was found that for the compound with x = 0.015 application of 1 T magnetic field in isothermal regime in the vicinity of the Curie temperature is accompanied by the entropy change 1.3 J/(Kkg).

Untypical Temperature Dependence of the Magnetocaloric Effect in the Dy(Co1-xFex)2 (x = 0.10; 0.15) Compounds

2015 ◽  
Vol 233-234 ◽  
pp. 247-250 ◽  
Author(s):  
Maksim S. Anikin ◽  
Evgeniy N. Tarasov ◽  
Nikolay V. Kudrevatykh ◽  
Aleksander V. Zinin
Keyword(s):  
Magnetic Field ◽  
Temperature Dependence ◽  
Magnetic Entropy Change ◽  
Magnetic Transition ◽  
Iron Concentration ◽  
Entropy Change ◽  
Cooling Power ◽  
X Ray Diffraction ◽  
Magnetocaloric Properties ◽  
Ordered State

A study of crystalline structure, magnetic and magnetocaloric properties of Dy(Co1-хFeх)2 (х = 0.10, 0.15) intermetallic compounds was undertaken. Phase composition was controlled by X-ray diffraction analysis. Magnetic properties were measured with a help of SQUID magnetometer in magnetic fields up to 7 Т in the temperature range from 4.2 K to 400 K. Magnetic transition temperatures from paramagnetic to magnetically ordered state were inferred as 288 K and 350 K, respectively. It is shown that at an increase of iron concentration and/or magnetic field intensity, a considerable maximum broadenings on a temperature dependence of magnetic entropy change is observed. The calculated value of the relative cooling power (RCP) of Dy(Co0.90Fe0.10)2, in a magnetic field of 1.7 T is equal to 152 J/kg that is close to that for Gd metal with RCP = 181 J/kg at μ0Н = 2 T.

Investigation of the Phase Composition of Lithium-Titanium Ferrites by Thermo-Magnetometric and X-Ray Analysis

2015 ◽  
Vol 1085 ◽  
pp. 233-236 ◽  
Author(s):  
Alexander L. Astafyev ◽  
Elena N. Lysenko ◽  
Anatoly P. Surzhikov
Keyword(s):  
Magnetic Field ◽  
Phase Composition ◽  
Magnetic Phase ◽  
Diffraction Method ◽  
Precise Estimate ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Gravimetric Measurements ◽  
Lithium Titanium

In the present work, the formation of the phase composition in the synthesis of lithium-titanium ferrite composition Li0.6Fe2.2Ti0.2O4 was investigated using thermo-magnetometry method based on thermo-gravimetric measurements in a magnetic field. Results of thermo-magnetometric analysis are compared with X-ray diffraction method data. It is shown that the thermo-magnetometry method better reflects the formation of the magnetic phase in the synthesis of ferrite, and therefore provides a more precise estimate the phase composition of the synthesis products.

Crystal structure and hyperfine interactions of delafossite (CuFeO2) synthesized hydrothermally

2021 ◽  
Vol 77 (4) ◽  
Author(s):  
Karolina Siedliska ◽  
Tomasz Pikula ◽  
Zbigniew Surowiec ◽  
Rafał Panek ◽  
Rafał Idczak ◽  
...  
Keyword(s):  
Room Temperature ◽  
Magnetic Transition ◽  
Hyperfine Interactions ◽  
Paramagnetic State ◽  
Copper Ferrite ◽  
X Ray Diffraction ◽  
Powder Specimen ◽  
X Ray ◽  
Delafossite Phase ◽  
Delafossite Cufeo2

The powder specimen of CuFeO2 delafossite was synthesized by a hydrothermal method at 453 K. X-ray diffraction studies confirmed that the obtained pure delafossite phase was a mixture of the 3R and 2H polytypes, predominantly the former. Mössbauer spectral analysis revealed the paramagnetic state of the copper ferrite at room temperature. Below 12 K the spectra had complicated shapes of Zeeman sextets. Changes in the character of the hyperfine interactions did not correspond to the data reported for the single-crystal CuFeO2. Magnetization measurements revealed that magnetic transition occurred at Néel temperature (T N) = 12.5 K.

Spin Reorientation Transition in Nanocrystalline (Pr,Sm)Fe8Ga3C Alloys

2010 ◽  
Vol 168-169 ◽  
pp. 126-129
Author(s):  
A.G. Popov ◽  
D.I. Gorbunov ◽  
G.V. Ivanova ◽  
G.M. Makarova ◽  
A.V. Korolyov
Keyword(s):  
Magnetic Field ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Spin Reorientation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spin Reorientation Transition ◽  
Plane Anisotropy ◽  
Cone Type ◽  
Ordered State

Spin-reorientation transitions in intermetallic (Pr1-xSmx)Fe8Ga3C compounds with the tetragonal BaCd11-type structure have been investigated. The magnetic phase diagram has been proposed for these compounds based on magnetic and X-Ray diffraction studies using their nanocrystalline ribbons and powders aligned in a magnetic field. In the concentration range 0 ≤ x ≤ 0.4 the compounds exhibit an «easy-plane» anisotropy at all temperatures of the magnetically ordered state. The magnetic anisotropy of the compounds with 0.5 ≤ x ≤ 1 is of the «easy-cone» type. The SmFe8Ga3C compound with the highest Sm content is a uniaxial ferromagnet with no indications of a spin-reorientation transition below its Curie temperature.

scholarly journals Photoluminescent Properties of Hydroxyapatite and Hydroxyapatite/Multi-Walled Carbon Nanotube Composites

Crystals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 832
Author(s):  
Edna X. Figueroa-Rosales ◽  
Javier Martínez-Juárez ◽  
Esmeralda García-Díaz ◽  
Daniel Hernández-Cruz ◽  
Sergio A. Sabinas-Hernández ◽  
...  
Keyword(s):  
Carbon Nanotube ◽  
Hexagonal Phase ◽  
Precipitation Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Multi Walled Carbon Nanotube ◽  
Nanotube Composites ◽  
Carbon Nanotube Composites ◽  
Co Precipitation ◽  
Functionalized Mwcnts

Hydroxyapatite (HAp) and hydroxyapatite/multi-walled carbon nanotube (MWCNT) composites were obtained by the co-precipitation method, followed by ultrasound-assisted and microwave radiation and thermal treatment at 250 °C. X-ray diffraction (XRD) confirmed the presence of a hexagonal phase in all the samples, while Fourier-transform infrared (FTIR) spectroscopy elucidated the interaction between HAp and MWCNTs. The photoluminescent technique revealed that HAp and the composite with non-functionalized MWCNTs present a blue luminescence, while the composite with functionalized MWCNTs, under UV-vis radiation shows an intense white emission. These findings allowed presentation of a proposal for the use of HAp and HAp with functionalized MWCNTs as potential materials for optoelectronic and medical applications.

scholarly journals Modeling of magneto-conductivity of bismuth selenide: a topological insulator

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Yogesh Kumar ◽  
Rabia Sultana ◽  
Prince Sharma ◽  
V. P. S. Awana
Keyword(s):  
Magnetic Field ◽  
Magnetic Fields ◽  
Single Crystal ◽  
Single Crystals ◽  
X Ray Diffraction ◽  
Field Range ◽  
X Ray ◽  
Bulk Carriers ◽  
Different Temperatures

AbstractWe report the magneto-conductivity analysis of Bi2Se3 single crystal at different temperatures in a magnetic field range of ± 14 T. The single crystals are grown by the self-flux method and characterized through X-ray diffraction, Scanning Electron Microscopy, and Raman Spectroscopy. The single crystals show magnetoresistance (MR%) of around 380% at a magnetic field of 14 T and a temperature of 5 K. The Hikami–Larkin–Nagaoka (HLN) equation has been used to fit the magneto-conductivity (MC) data. However, the HLN fitted curve deviates at higher magnetic fields above 1 T, suggesting that the role of surface-driven conductivity suppresses with an increasing magnetic field. This article proposes a speculative model comprising of surface-driven HLN and added quantum diffusive and bulk carriers-driven classical terms. The model successfully explains the MC of the Bi2Se3 single crystal at various temperatures (5–200 K) and applied magnetic fields (up to 14 T).

Mechanically Driven Dissolution of Sn in Near-Equiatomic Bcc FeCo

2012 ◽  
Vol 194 ◽  
pp. 187-193 ◽  
Author(s):  
J.M. Loureiro ◽  
Benilde F.O. Costa ◽  
Gerard Le Caër ◽  
Bernard Malaman
Keyword(s):  
Magnetic Field ◽  
Solid Solutions ◽  
Room Temperature ◽  
Hyperfine Magnetic Field ◽  
Ternary Alloys ◽  
119Sn Mössbauer Spectroscopy ◽  
X Ray Diffraction ◽  
Mechanically Alloyed ◽  
Powder Mixtures ◽  
X Ray

Ternary alloys, (Fe50−x/2Co50−x/2)Snx(x ≤ 33 at.%), are prepared by mechanical alloying from powder mixtures of the three elements. As-milled alloys are studied by X-ray diffraction and 57Fe and 119Sn Mössbauer spectroscopy. The solubility of Sn in near-equiatomic bcc FeCo is increased from ~0.5 at. % at equilibrium to ~20 at.% in the used milling conditions. The average 119Sn hyperfine magnetic field at room temperature is larger, for any x, than the corresponding fields in mechanically alloyed Fe-Sn solid solutions.

Microstructure Evolution and Mossbauer Spectroscopy Research of Nanostructured Ni3 Fe Intermetallic

2021 ◽  
Vol 32 ◽  
pp. 1-13
Author(s):  
Amel Kaibi ◽  
Abderrahim Guittoum ◽  
Nassim Souami ◽  
Mohamed Kechouane
Keyword(s):  
Magnetic Field ◽  
Mössbauer Spectroscopy ◽  
Mössbauer Spectra ◽  
Milling Time ◽  
Mossbauer Spectroscopy ◽  
Hyperfine Magnetic Field ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mossbauer Spectra ◽  
Mößbauer Spectroscopy

Nanocrystalline Ni75Fe25 (Ni3Fe) powders were prepared by mechanical alloying process using a vario-planetary high-energy ball mill. The intermetallic Ni3Fe formation and different physical properties were investigated, as a function of milling time, t, (in the range 6 to 96 h range), using X-Ray Diffraction (XRD) and Mössbauer Spectroscopy techniques. X-ray diffraction were performed on the samples to understand the structural characteristics and get information about elements and phases present in the powder after different time of milling. The refinement of XRD spectra revealed the complete formation of fcc Ni (Fe) disordered solid solution after 24 h of milling time, the Fe and Ni elemental distributions are closely correlated. With increasing the milling time, the lattice parameter increases and the grains size decreases. The Mössbauer experiments were performed on the powders in order to follow the formation of Ni3Fe compound as a function of milling time. From the adjustment of Mössbauer spectra, we extracted the hyperfine parameters. The evolution of hyperfine magnetic field shows that the magnetic disordered Ni3Fe phase starts to form from 6 h of milling time and grow in intensity with milling time. For the milling time more than 24 h, only the Ni3Fe disordered phase is present with a mean hyperfine magnetic field of about 29.5 T. The interpretation of the Mossbauer spectra confirmed the results obtained by XRD.

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