Magnetic properties of undoped and Co-doped n-type β–FeSi2.5 single crystals

2002 ◽  
Vol 17 (11) ◽  
pp. 2960-2965 ◽  
Author(s):  
E. Arushanov ◽  
L. Ivanenko ◽  
D. Eckert ◽  
G. Behr ◽  
U. K. Rößler ◽  
...  

Results of magnetization and magnetic susceptibility measurements on undoped and Co-doped FeSi2.5 single crystals are presented. The temperature dependence of the magnetic susceptibility of the Co-doped sample in the range of 5–300 K can be explained by temperature-dependent contributions due to paramagnetic centers and the carriers excited thermally in the extrinsic conductivity region. The values of the paramagnetic Curie temperature and activation energy of the donor levels were estimated. It is also shown that the magnetic susceptibility of Co-doped samples cooled in zero external field and in a field are different. This resembles the properties of spin-glasses and indicates the presence of coupling between magnetic centers.

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 378
Author(s):  
Li Zhao ◽  
Zhiwei Hu ◽  
Hanjie Guo ◽  
Christoph Geibel ◽  
Hong-Ji Lin ◽  
...  

We report on the synthesis and physical properties of cm-sized CoGeO3 single crystals grown in a high pressure mirror furnace at pressures of 80 bar. Direction dependent magnetic susceptibility measurements on our single crystals reveal highly anisotropic magnetic properties that we attribute to the impact of strong single ion anisotropy appearing in this system with TN∼33.5 K. Furthermore, we observe effective magnetic moments that are exceeding the spin only values of the Co ions, which reveals the presence of sizable orbital moments in CoGeO3.


2012 ◽  
Vol 190 ◽  
pp. 97-100 ◽  
Author(s):  
V.V. Glushkov ◽  
A.V. Kuznetsov ◽  
I. Sannikov ◽  
A.V. Bogach ◽  
S.V. Demishev ◽  
...  

We report the magnetic properties of EuxCa1-xB6 single crystals (0.756x1) studied in the wide range of temperatures (1.8-300 K) and magnetic fields (up to 50 kOe). It was found that low field magnetic susceptibility χ (T) follows the Curie-Weiss law χ~(T-Θp)-1 at high temperatures for all the concentrations studied. The effective magnetic moment of the Eu2+ ion estimated from the data diminishes from the free ion value μeff7.93μB (μB - Bohr magneton) for x=1 to μeff7.3μB for x=0.756. A universal behavior of magnetic susceptibility χ~(T-Θ)-α (α=1.5) is detected close to the Curie temperature TC in the paramagnetic state at both metallic (x>xC~0.8) and dielectric (xC.


2021 ◽  
Author(s):  
Sandra B. Ramírez-García ◽  
Luis M. Alva-Valdivia

<p>Magnetite formation of serpentinized ultramafic rocks leads to variations in the magnetic properties of serpentinites; however, magnetite precipitation is still on debate.</p><p>In this work, we analyzed 60 cores of ultramafic rocks with a variety of serpentinization degrees. These rocks belong to the ultramafic-mafic San Juan de Otates complex in Guanajuato, Mexico. Geochemical studies have been previously conducted, enabling us to compare changes in the magnetic properties against the chemical variations generated by the serpentinization process. By studying the density and magnetic properties such as anisotropy of magnetic susceptibility, hysteresis curves as well as magnetic and temperature-dependent susceptibility and, we were able to identify the relationship between magnetic content and serpentinization degree, the predominant magnetic carrier, and to what extent the magnetite grain size depends on the serpentinization.  Variations in these parameters allowed us to better constrain the temperature at which serpentinization occurred, the generation of other Fe-rich phases such as Fe-brucite and/or Fe-rich serpentine as well as distinctive rock textures formed at different serpentinization degrees.</p>


2018 ◽  
Vol 185 ◽  
pp. 04007 ◽  
Author(s):  
A.N. Taldenkov ◽  
A.V. Inyushkin ◽  
E.A. Chistotina ◽  
V.G. Ralchenko ◽  
A.P. Bolshakov ◽  
...  

The magnetic properties of single crystals of synthetic diamond and crystals of silicon carbide were studied. High-purity samples of diamonds synthesized with HPHT and CVD technologies were used. The crystals of silicon carbide were grown by sublimation and industrial technology. Along with samples with a natural isotopic composition, monoisotopic crystals of diamond (99.96% 12C and 99.96% 13C) and silicon carbide (99.993% of 28Si) were studied. On the basis of the data obtained, the diamagnetic susceptibility was determined and the concentration of paramagnetic centers and the content of the ferromagnetic component were evaluated. The results are discussed.


1996 ◽  
Vol 452 ◽  
Author(s):  
J. Hack ◽  
M. H. Ludwig ◽  
W. Geerts ◽  
R. E. Hummel

AbstractMagnetic properties of photoluminescing spark-processed silicon (sp-Si) have been investigated for the first time. Contrary to the diamagnetic signal known for bulk silicon, sp-Si displays a paramagnetic resonance as well as a ferromagnetic hysterisis loop. The paramagnetic resonance was studied using an EPR system and showed a high concentration of at least two distinct paramagnetic centers. One center can be eliminated by annealing in Ultra-High Purity nitrogen for 30 minutes at 600 °C. Measurements utilizing a SQUID magnetometer revealed that sp-Si displays ferromagnetic ordering with a saturization magnetization occuring at low fields. This is attributed to the high density of paramagnetic centers. Temperature dependent measurements were performed to establish possible links between magnetic properties and the luminescence of sp-Si.


1994 ◽  
Vol 49 (9) ◽  
pp. 1239-1242 ◽  
Author(s):  
Ayhan Elmali ◽  
Yalcin Elerman ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  

[FeL(MeOH)Cl]2 (L = N-(2-hydroxyphenyl)salicylaldimine) was synthesized and its crystal structure determined, [C27H20N 2O5Cl2Fe2], monoclinic, space group P21/c, a = 9.528(1), b = 7.684(1), c = 18.365(2) Å, β = 109.83(1)°, V = 1264.8 Å3, Z = 2. Two identical [FeL(MeOH)Cl] fragments, related by an inversion centre, are combined by the two bridging O atoms, to form a binuclear unit. The iron(III) centers are separated by 3.163(2) Å and weakly antiferromagnetically coupled (J = -8 .0 (1 ) cm-1), which follows from temperature - dependent magnetic susceptibility measurements in the range 4.2 to 288 K. The effective magnetic moment per iron(III) is μeff = 7.4 μB at 288 K


1998 ◽  
Vol 12 (28) ◽  
pp. 1175-1183 ◽  
Author(s):  
I. Gr. Deac ◽  
A. V. Pop ◽  
V. Pop ◽  
R. Tetean ◽  
D. Kovacs ◽  
...  

The electrical and magnetic properties of ( Y 1-x-y Zr x Ca y) Ba 2 Cu 3 O 7-δ ceramics are investigated by using resistivity, ac and dc susceptibility measurements. X-ray powder diffraction has been used to find the lattice parameters of the samples. The samples are orthorhombic, except the sample with x=0.15 and y=0.2 which is tetragonal. All the samples are superconducting. There is no significant change in Tc for the Zr-doped ( Y 1-x Zr x) Ba 2 Cu 3 O 7-δ samples, while for the ( Y 0.85-y Zr 0.15 Ca y) Ba 2 Cu 3 O 7-δ compounds the Tc decrease with the dopant content and they show temperature dependent dc magnetic susceptibility, in the normal state.


2011 ◽  
Vol 66 (11) ◽  
pp. 1097-1100 ◽  
Author(s):  
Larysa Shlyk ◽  
Rainer Niewa

Single crystals of the new barium hollandite Ba1.3Co1.3Ti6.7O16 were obtained from a BaCl2 flux (I2/m, Z = 1, a = 9.9470(4), b = 2.9714(2), c = 10.2260(5) Å , β = 90.906(2)◦). In the crystal structure piles of Ba atoms are situated within a framework of edge- and vertex-sharing octahedra (Co,Ti)O6. The composition was deduced from microprobe analyses, structure refinements and charge balance arguments in agreement with the observed magnetic properties. The temperature dependence of the magnetic susceptibility χ(T) of Ba1.3Co1.3Ti6.7O16 single crystals reveals paramagnetism down to 2 K. The value of the Co magnetic moment deduced from the Curie-Weiss law agrees well with the theoretical value of the high-spin state spin-only moment of μeff = 3.87 μB for Co2+ (S = 3/2)


2004 ◽  
Vol 19 (8) ◽  
pp. 2517-2517
Author(s):  
E. Arushanov ◽  
L. Ivanenko ◽  
D. Eckert ◽  
G. Behr ◽  
U.K. Rößler ◽  
...  

In the title of this paper (and also in several places in the text), the chemical notation for the orthorhombic semiconducting iron disilicide is given incorrectly. In the whole paper, the chemical formula “β-FeSi2.5” should be replaced by the formula “β-FeSi2”.


1996 ◽  
Vol 51 (8) ◽  
pp. 1132-1136 ◽  
Author(s):  
Yalcin Elerman ◽  
Mehmet Kabak ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  

[Methylamino-(N,N′-1,3-propyl-disalicylaldiminato)-Ni(II)-bis-(N-methylsalicylaldiminato)- Ni(II)] was synthesized from the condensation of N,N′-1,3-propyl-disalicylaldimine, salicylaldehyde, methylaminohydrochloride, NaOH and Ni(CH3COO)2·H2O, and its crystal structure determined. [C34H37N5O4Ni2], orthorhombic, space group Pbca, a = 12.330( 1), b = 24.967(2), c = 20.616(2)Å, Z = 8. The dinuclear complex contains two octahedrally coordinated nickel atoms which are linked via three oxygen atoms with an average (Ni-O-Ni) angle of 87.2( 1)° and a Ni···Ni distance of 2.884(1)Å. The coordination is completed by three nitrogen atoms. The nickel(II) centers are ferromagnetically coupled (J = 11.5 cm-1) as derived from temperature-dependent magnetic susceptibility measurements in the range 5 - 280 K.


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