Magnetic properties of Apollo 12 lunar samples

The magnetic properties of crystalline rock and fines returned by the Apollo 12 mission have been measured. The fines contain at least 0.7% by mass of native iron, mainly in the super- paramagnetic form at room temperature. Native iron is present in the crystalline rock but in a much lower concentration. The paramagnetic minerals, ilmenite and ulvöspinel, are present. Some evidence has been obtained that magnetite is present in the crystalline rock, less than 0.02% by mass. It has not yet been established whether it is indigenous to the rock. Two samples exhibit a change in n.r.m. at low temperature consistent with this n.r.m. being carried by magnetite, but these investigations are not yet complete. The crystalline rocks possess an n.r.m. of intermediate stability: there is evidence for two components of magnetization, a weak and rather stable one, and a less stable but stronger component. The former indicates the presence of a magnetic field on the moon at the time of formation of the rocks. An external origin seems unlikely: thus the Moon possessed a magnetic field of internal origin 3400 Ma§ ago which has since decayed.

2011 ◽  
Vol 687 ◽  
pp. 500-504
Author(s):  
S. X. Xue ◽  
S.S. Feng ◽  
P. Y. Cai ◽  
Q T Li ◽  
H. B. Wang

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.


1991 ◽  
Vol 05 (01n02) ◽  
pp. 3-30 ◽  
Author(s):  
J. Carmelo ◽  
P. Horsch ◽  
P.A. Bares ◽  
A.A. Ovchinnikov

The Landau-Luttinger liquid formulation is used to investigate the physics of the one-dimensional Hubbard model in a magnetic field of arbitrary strength H. The low lying charge and spin excitations are studied. A novel branch of sound wave-like spin excitations arises for H>0. The low temperature thermodynamics is considered in some detail.


1991 ◽  
Vol 05 (21) ◽  
pp. 1447-1456 ◽  
Author(s):  
A. R. HARUTUNYAN ◽  
L. S. GRIGORYAN ◽  
A. S. KUZANYAN ◽  
A. A. KUZNETSOV ◽  
A. A. TERENTIEV ◽  
...  

Two samples of benzene-treated Bi–Pb–Sr–Ca–Cu–O powder exhibited at 300 K magnetic field dependent diamagnetism and magnetization irreversibility. The treatment with benzene resulted also in the appearance of microwave absorption at low magnetic fields, while is sensitive to magnetic history of the sample. From X-ray diffraction data one can see that upon benzene treatment the reflections of 85 K and 110 K phases do not change practically, but a series of new reflections appeared, indicating a lattice modulation with 4.9 nm periodicity. A microprobe analysis revealed substantial inhomogeneity of chemical composition across the samples. The room temperature anomalies were weakened in one sample and vanished in the second upon thermal cycling.


2019 ◽  
Vol 33 (12) ◽  
pp. 1950113 ◽  
Author(s):  
I. M. Pazukha ◽  
Y. O. Shkurdoda ◽  
A. M. Chornous ◽  
L. V. Dekhtyaruk

A series of thin-film nanocomposites based on ferromagnetic metal Co and insulator SiO were prepared using an electron-beam method. The magnetoresistive and magnetic properties of these structures deposited at room temperature and then annealed to 700 K were investigated. The results showed that at the Co concentration 40 [Formula: see text]x [Formula: see text] 60 at.%, thin-film nanocomposites exhibit magnetoresistance (MR) that is conditional on spin-dependent tunnelling of electrons. This range of concentrations corresponds to the prepercolation area according to the magnetic investigations. For samples with x [Formula: see text] 70 at.%, the anisotropic character of MR peculiar to the homogeneous ferromagnetic materials appears. According to the magnetic properties study, this range of concentrations corresponds to the area after transition through the percolation threshold. The annealing process in temperature range from 300 K to 700 K in the magnetic field slightly influenced the magnetoresistive properties of the thin-film nanocomposites based on Co and SiO for all range of concentrations.


2013 ◽  
Vol 750-752 ◽  
pp. 426-430
Author(s):  
Zhao Yang Cheng ◽  
Jing Liu ◽  
Wen Si Chen ◽  
Guo Dong Sun ◽  
Xi Feng Lin ◽  
...  

Fe-6.5wt%Si silicon steel has excellent soft magnetic properties, but its ductility in room temperature is near zero. A lot of researchers tried to improve the ductility by adding alloy elements. In this paper, we summarized the action mechanism and the content of these alloy elements according to the overseas and domestic research status. Al, B, Cr, RE, et al. improved the ductility of Fe-6.5wt%Si silicon steel in low temperature, but reduced its magnetic properties simultaneously. Ni, Ti, Mn, et al. improved the ductility of Fe-6.5wt%Si silicon steel inconspicuously.


2002 ◽  
Vol 16 (20n22) ◽  
pp. 2960-2963 ◽  
Author(s):  
E. D. JONES ◽  
J. L. RENO ◽  
S. CROOKER ◽  
K. K. BAJAJ ◽  
G. COLI

Low temperature diamagnetic shifts and FWHM linewidths of excitonic transitions in Al x Ga 1-x As alloys are reported as a function of magnetic field (50T maximum) at 4K using photoluminescence spectroscopy. Two samples with aluminum compositions of 5 and 20%, are discussed. The slope of the diamagnetic shift at high fields allows a direct measure of the excitonic reduced mass μ.


2014 ◽  
Vol 24 (3S1) ◽  
pp. 90-94 ◽  
Author(s):  
Le Tuan Tu ◽  
Luu Van Thiem ◽  
Pham Duc Thang

The magnetic properties in Co-Ni-P nanowires arrays with diameter of 200 nm were investigated. All the samples were prepared by electrodeposition method with pH of 5.5 and at room temperature. During the deposition, a magnetic field in range of 0 - 750 Oe was applied parallel to the wires axis. The crystalline structure and morphology of the samples were characterized by X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM), respectively. The hysteresis loops were measured at room temperature using vibrating sample magnetometry (VSM). The mixture of hcp phases of the Co-Ni-P based nanowires has been indicated by the XRD pattern. The obtained results show that with 750 Oe magnetic field applied during deposition we can obtain maximum coercivity value (2180 Oe). The \(M_{r}/M_{s}\) ratio was rapid increased when the magnetic field changed from 0 Oe to 750 Oe.


2019 ◽  
Vol 7 (1) ◽  
pp. 53-68 ◽  
Author(s):  
D. Ravi Kumar ◽  
Syed Ismail Ahmad ◽  
Ch. Abraham Lincoln ◽  
D. Ravinder

2012 ◽  
Vol 194 ◽  
pp. 104-107 ◽  
Author(s):  
Piotr Urbanowicz ◽  
Elzbieta Tomaszewicz ◽  
Tadeusz Groń ◽  
Henryk Duda ◽  
Slawomir Mazur ◽  
...  

Magnetic susceptibility measurements showed both a weak response to magnetic field and a lack of the Curie-Weiss region for CuEu2W2O10and Cu3Eu2W4O18tungstates characteristic for the multiplet widths comparable to thermal energy. Magnetization measurements displayed the linear temperature dependence with the lower magnetic moment for Cu3Eu2W4O18in comparison with CuEu2W2O10, indicating that the effect of the electric charges associated with the surrounding ligands can change the multiplet width of individual states. It is affecting the electrical properties of examined tungstates which reveal the insulating state and low relative permittivity εr ~ 29 in case of CuEu2W2O10and the thermally activated p-type electrical conduction for Cu3Eu2W4O18with the activation energy of 1.11 eV and the large value of εr ~ 217 above the room temperature.


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