Variations in magnetic properties of Mexican serpentinites and related micro-textures 

2021 ◽  
Author(s):  
Sandra B. Ramírez-García ◽  
Luis M. Alva-Valdivia
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Anisotropy Of Magnetic Susceptibility ◽  
Ultramafic Rocks ◽  
Magnetic Carrier ◽  
Temperature Dependent ◽  
Geochemical Studies ◽  
The Relationship ◽  
Magnetite Formation

<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>

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 ◽  
...  
Keyword(s):  
Activation Energy ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
External Field ◽  
Single Crystals ◽  
Spin Glasses ◽  
Paramagnetic Centers ◽  
Temperature Dependent ◽  
Paramagnetic Curie Temperature ◽  
Co Doped

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.

Structure and Magnetic Properties of a Dinuclear Complex with Iron(III) in Octahedral and Pyramidal Coordination

1994 ◽  
Vol 49 (9) ◽  
pp. 1239-1242 ◽  
Author(s):  
Ayhan Elmali ◽  
Yalcin Elerman ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Magnetic Moment ◽  
Effective Magnetic Moment ◽  
Dinuclear Complex ◽  
Monoclinic Space Group ◽  
Temperature Dependent ◽  
Space Group ◽  
Binuclear Unit

[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

Superconductivity and Normal-State Properties of (Y1-x-yZrxCay)Ba2Cu3O7-δ Compounds

1998 ◽  
Vol 12 (28) ◽  
pp. 1175-1183 ◽  
Author(s):  
I. Gr. Deac ◽  
A. V. Pop ◽  
V. Pop ◽  
R. Tetean ◽  
D. Kovacs ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Powder Diffraction ◽  
Normal State ◽  
Lattice Parameters ◽  
Temperature Dependent ◽  
Dopant Content ◽  
X Ray ◽  
Electrical And Magnetic Properties ◽  
Normal State Properties

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.

Structure and Magnetic Properties of a Triply Oxygen. Bridged Dinuclear Ni(II) Complex

1996 ◽  
Vol 51 (8) ◽  
pp. 1132-1136 ◽  
Author(s):  
Yalcin Elerman ◽  
Mehmet Kabak ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Dinuclear Complex ◽  
Temperature Dependent ◽  
Orthorhombic Space Group ◽  
Space Group ◽  
Oxygen Atoms

[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.

Effects of Sputtering Conditions on Texture, Microstructure and Magnetic Properties of the CoCrPt/NiAl Thin Films

1998 ◽  
Vol 517 ◽  
Author(s):  
Y.-N. Hsu ◽  
D. E. Laughlin ◽  
D. N. Lambeth
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Magnetic Properties ◽  
Optimum Pressure ◽  
Grain Sizes ◽  
Maximum Value ◽  
Sputtering Power ◽  
Sputtering Pressure ◽  
The Relationship ◽  
Microstructure And Magnetic Properties

AbstractThe effects of sputtering argon pressures and sputtering power on the microstructure, texture and magnetic properties of NiAI underlayers on CoCrPt films were investigated. In this paper, the relationship between the sputtering conditions, microstructure, crystallographic texture and magnetic properties of these thin films will be discussed. By controlling the sputtering pressure and sputtering power, the texture and microstructure of NiAI underlayers were found to vary. This in turn was found to influence the magnetic properties of CoCrPt thin films. It was found that 10 mtorr is the optimum pressure to deposit the NiAl thin films to obtain the best magnetic properties for our system. At this argon pressure, the coercivity reached a maximum value because of the strongest CoCrPt (1010) texture and smallest grain size. At lower argon pressures (< 10 mtorr), NiAI tended to have a (110) texture reducing the CoCrPt (1010) texture, which in turn reduced the CoCrPt coercivity and S*. Also, high NiAl deposition pressures (>30 mtorr) yielded larger grains and a weaker CoCrPt (1010) texture, thereby decreasing the coercivity of the CoCrPt films. Increasing the sputtering power has been found to increase the CoCrPt coercivity and S* value. However, the grain sizes of the CoCrPt/NiAl thin films deposited at higher sputtering power were larger than those obtained at lower sputtering power.

scholarly journals Magnetic Properties of a Holocene Sediment Core from the Yeongsan Estuary, Southwest Korea: Implications for Diagenetic Effects and Availability as Paleoenvironmental Proxies

2021 ◽  
Vol 9 ◽  
Author(s):  
Hyeon–Seon Ahn ◽  
Jaesoo Lim ◽  
Sung Won Kim
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
South Korea ◽  
Size Distribution ◽  
Sea Level ◽  
West Coast ◽  
Magnetic Minerals ◽  
The West ◽  
Saturation Moment

The sensitivity of magnetic properties, which characterize the mineralogy, concentration, and grain size distribution of magnetic minerals, to environmental processes may provide useful information on paleoenvironmental changes in estuarine environments. Magnetic property studies of estuaries are less common than other environments and, due to the west coast of South Korea having an abundance of estuaries, it provides a good place to study these processes. In this study, we analyzed a variety of magnetic properties based on magnetic susceptibility, hysteresis parameters, progressive acquisition of isothermal remanent magnetization and first-order reversal curve data from a Holocene muddy sediment core recovered from the Yeongsan Estuary on the west coast of South Korea. We examined diagenetic effects on magnetic properties and tested their availability as proxies of paleoenvironmental change. The presence of generally low magnetic susceptibility, ubiquitous greigite-like authigenic magnetic component, and very fine magnetic particle occurrence suggested that the analyzed sediments had undergone considerable early diagenetic alteration. Electron microscopic observations of magnetic minerals support this suggestion. Our results confirm that the use of initial bulk susceptibility as a stand-alone environmental change proxy is not recommended unless it is supported by additional magnetic analyses. We recognized the existence of ferromagnetic-based variabilities related to something besides the adverse diagenetic effects, and have examined possible relationships with sea-level and major climate changes during the Holocene. The most remarkable finding of this study is the two distinct intervals with high values in magnetic coercivity (Bc), coercivity of remanence (Bcr), and ratio of remanent saturation moment to saturation moment (Mrs/Ms) that were well coincident with the respective abrupt decelerations in the rate of sea-level rise occurred at around 8.2 and 7 thousand years ago. It is then inferred that such condition with abrupt drop in sea-level rise rate would be favorable for the abrupt modification of grain size distribution toward more single-domain-like content. We modestly propose consideration of the Bc, Bcr, and Mrs/Ms variability as a potential indicator for the initiation/occurrence of sea-level stillstand/slowstand or highstand during the Holocence, at least at estuarine environments in and around the studied area.

X-Ray Structure and Magnetic Properties of the Tetracupferronato-bis(μ-methoxy)-diiron(III) Complex

1995 ◽  
Vol 50 (11) ◽  
pp. 1587-1590 ◽  
Author(s):  
Yalcin Elerman ◽  
Mehmet Kabak ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Exchange Interaction ◽  
Monoclinic Space Group ◽  
Antiferromagnetic Exchange ◽  
Temperature Dependent ◽  
Space Group ◽  
X Ray ◽  
Antiferromagnetic Exchange Interaction

The tetracupferronato-bis(μ-methoxy)-diiron(III) complex has been synthesized in acetonitrile and its crystal structure determined. C26H26N8O10Fe2, monoclinic, space group C2/c, a =18.425(3), b = 12.999(2), c = 15.046(3) Å, β = 124.66(2)°,V = 2964(1) Å3, Z = 4, wR(2) = 0.097 from 1491 reflections (F2). Two iron(III) atoms are at special positions in six-fold coordination, bridged by O with a Fe-O-Fe angle of 102.4(1)° and a distance between two iron(III) centers of 3.075(1) Å. Temperature-dependent magnetic susceptibility measurements reveal a antiferromagnetic exchange interaction (J = -14 cm-1) between the iron(III) centers.

Structure and Magnetic Properties of a (μ-Oxo)diiron(III) Complex

1993 ◽  
Vol 48 (3) ◽  
pp. 313-317 ◽  
Author(s):  
Ayhan Elmali ◽  
Yalcin Elerman ◽  
Ingrid Svoboda ◽  
Hartmut Fuess ◽  
Klaus Griesar ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Oxygen Atom ◽  
Monoclinic Space Group ◽  
Temperature Dependent ◽  
Space Group

μ-Oxo-bis[N ,N '-o-phenylene-di(salicylaldiminato)iron(III)] was synthesized in dioxane solvent and its crystal structure determined. [C2OH14N ,OiFe]-,O · (C4H8O2), monoclinic, space group P21/ c ,a = 14.650(2), b = 18.990(1), c = 13.296(1) Å, β = 76.080(7), V = 3590.3 Å3, Z = 4. Two iron (III) atoms in square pyramidal pentacoordination are bridged by an oxygen atom with an Fe - O - Fe angle of 145 and a Fe-Fe distance of 3.409(1) Å. The iron (III) centers are antiferrommagnetically coupled (J = -9 8 .5 cm-1), as derived from temperature-dependent magnetic susceptibility measurements in the range 4.2 to 286.5 K.

scholarly journals Copper(II) Halide Salts with 1-(4′-Pyridyl)-Pyridinediium

Inorganics ◽  
2020 ◽  
Vol 8 (3) ◽  
pp. 18 ◽  
Author(s):  
Jeffrey C. Monroe ◽  
Christopher P. Landee ◽  
Melanie Rademeyer ◽  
Mark M. Turnbull
Keyword(s):  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Hydrogen Bonding ◽  
Room Temperature ◽  
Crystal Packing ◽  
Monoclinic Space Group ◽  
Antiferromagnetic Exchange ◽  
Temperature Dependent ◽  
Packing Arrangement ◽  
Halide Salts

The compounds [1,4′-bipyridine]-1,1′-diium [CuCl4] (1) and [1,4′-bipyridine]-1,1′-diium [CuBr4] (2) were prepared and their crystal structures and magnetic properties are reported. The compounds are isomorphous and crystallize in the monoclinic space group C2/c. The cation crystallizes in a two-fold disordered fashion with the terminal nitrogen and carbon atoms exhibiting 50% occupancies. This results in a crystal packing arrangement with significant hydrogen bonding that is very similar to that observed in the corresponding 4,4′-bipyridinediium complexes. Temperature dependent magnetic susceptibility measurements and room temperature EPR spectroscopy indicate the presence of very weak antiferromagnetic exchange. The data were fit to the Curie–Weiss law and yielded Weiss constants of −0.26(5) K (1) and −1.0(1) K (2).

Magnetic Properties and Crystal Structure of a 3,5-Dimethylpyrazolate-Bridged Binuclear Copper(II) Complex

2001 ◽  
Vol 56 (10) ◽  
pp. 970-974 ◽  
Author(s):  
Y. Elerman ◽  
A. Elmali
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Magnetic Susceptibility ◽  
Dihedral Angle ◽  
Coordination Sphere ◽  
Magnetic Moment ◽  
Binuclear Copper ◽  
Temperature Dependent ◽  
Orthorhombic Space Group ◽  
Square Planar

[Cu2L(prz)] (prz = 3,5-dimethylpyrazole and L = 1,3-bis(5-bromo-2-hydroxybenzylidene)- propan-2-ol) was synthesized and its crystal structure determined. It crystallizes in the orthorhombic space group Pbca with a = 14.160(9), b = 15.109(4), c = 21.298(5) Å, V = 4557(1) A3, Z = 8 . Two copper(II) ions are in a square-planar coordination. The metal coordination sphere is four-coordinate, with a planar N2O2 donor set. The dihedral angle between the two coordination planes is 12.14(7)°. The copper(II) centers are separated by 3.365(1) Å and antiferromagnetically coupled (J = -214.3 cm-1), which follows from temperature-dependent magnetic susceptibility measurements in the temperature range 4.6 to 310 K. The Cu-O-Cu angle is 125.9(1)° in the super-exchange pathway. The magnetic moment at 310 K is ca. 1.76 B.M. and 0.13 B.M. at 4.6 K.

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