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Articles 1 - 10 of 10
Full-Text Articles in Physical Sciences and Mathematics
Structure And Magnetism Of Co2ge Nanoparticles, Onur Tosun, Frank M. Abel, Balamurugan Balasubramanian, Ralph Skomski, David J. Sellmyer, George C. Hadjipanayis
Structure And Magnetism Of Co2ge Nanoparticles, Onur Tosun, Frank M. Abel, Balamurugan Balasubramanian, Ralph Skomski, David J. Sellmyer, George C. Hadjipanayis
Nebraska Center for Materials and Nanoscience: Faculty Publications
The structural and magnetic properties of Co2Ge nanoparticles (NPs) prepared by the cluster-beam deposition (CBD) technique have been investigated. As-made particles with an average size of 5.5 nm exhibit a mixture of hexagonal and orthorhombic crystal structures. Thermomagnetic measurements showed that the as-made particles are superparamagnetic at room temperature with a blocking temperature (TB) of 20 K. When the particles are annealed at 823 K for 12 h, their size is increased to 13 nm and they develop a new orthorhombic crystal structure, with a Curie temperature (TC) of 815 K. This …
Structural, Magnetic, And Mössbauer Studies Of Transition Metal-Doped Gd2fe16ga0.5tm0.5 Intermetallic Compounds (Tm = Cr, Mn, Co, Ni, Cu, And Zn), Jiba Dahal, K. S. Syed Ali, S. R. Mishra, J. Alam
Structural, Magnetic, And Mössbauer Studies Of Transition Metal-Doped Gd2fe16ga0.5tm0.5 Intermetallic Compounds (Tm = Cr, Mn, Co, Ni, Cu, And Zn), Jiba Dahal, K. S. Syed Ali, S. R. Mishra, J. Alam
Department of Physics and Astronomy Faculty Publications
The effect of transition metal substitution for Fe and the structural and magnetic properties of Gd2Fe16Ga0.5TM0.5 (TM = Cr, Mn, Co, Ni, Cu, and Zn) compounds were investigated in this study. Rietveld analysis of X-ray data indicates that all the samples crystallize in the hexagonal Th2Ni17 structure. The lattice parameters a, c, and the unit cell volume show TM ionic radii dependence. Both Ga and TM atoms show preferred site occupancy for 12j and 12k sites. The saturation magnetization at room temperature was observed for Co, Ni, and Cu of …
The Assessment Of Geothermal Potential Of Turkey By Means Of Heat Flow Estimation, Uğur Akin, Emin U. Ulugergerli̇, Semih Kutlu
The Assessment Of Geothermal Potential Of Turkey By Means Of Heat Flow Estimation, Uğur Akin, Emin U. Ulugergerli̇, Semih Kutlu
Bulletin of the Mineral Research and Exploration
In this study, the heat flow distribution of Turkey was investigated in the interest of exploring new geothermal fields in addition to known ones. For this purposes, the geothermal gradient was estimated from the Curie point depth map obtained from airborne magnetic data by means of power spectrum method. By multiplying geothermal gradient with thermal conductivity values, the heat flow map of Turkey was obtained. The average value in the heat flow map of Turkey was determined as 74 mW/m2. It points out existence of resources of geothermal energy larger than the average of the world resources. in …
Role Of Oxygen Electrons In The Metal-Insulator Transition In The Magnetoresistive Oxide La2-2xsr1+2xmn2o7 Probed By Compton Scattering, B. Barbiellini, A. Koizumi, P. E. Mijnarends, W. Al-Sawai, Hsin Lin, T. Nagao, K. Hirota, M. Itou, Y. Sakurai, A. Bansil
Role Of Oxygen Electrons In The Metal-Insulator Transition In The Magnetoresistive Oxide La2-2xsr1+2xmn2o7 Probed By Compton Scattering, B. Barbiellini, A. Koizumi, P. E. Mijnarends, W. Al-Sawai, Hsin Lin, T. Nagao, K. Hirota, M. Itou, Y. Sakurai, A. Bansil
Bernardo Barbiellini
We have studied the [100]-[110] anisotropy of the Compton profile in the bilayer manganite. Quantitative agreement is found between theory and experiment with respect to the anisotropy in the two metallic phases (i.e., the low temperature ferromagnetic and the colossal magnetoresistant phase under a magnetic field of 7 T). Robust signatures of the metal-insulator transition are identified in the momentum density for the paramagnetic phase above the Curie temperature. We interpret our results as providing direct evidence for the transition from the metalliclike to the admixed ionic-covalent bonding accompanying the magnetic transition. The number of electrons involved in this phase …
Role Of Oxygen Electrons In The Metal-Insulator Transition In The Magnetoresistive Oxide La2-2xsr1+2xmn2o7 Probed By Compton Scattering, B. Barbiellini, A. Koizumi, P. E. Mijnarends, W. Al-Sawai, Hsin Lin, T. Nagao, K. Hirota, M. Itou, Y. Sakurai, A. Bansil
Role Of Oxygen Electrons In The Metal-Insulator Transition In The Magnetoresistive Oxide La2-2xsr1+2xmn2o7 Probed By Compton Scattering, B. Barbiellini, A. Koizumi, P. E. Mijnarends, W. Al-Sawai, Hsin Lin, T. Nagao, K. Hirota, M. Itou, Y. Sakurai, A. Bansil
Hsin Lin
We have studied the [100]-[110] anisotropy of the Compton profile in the bilayer manganite. Quantitative agreement is found between theory and experiment with respect to the anisotropy in the two metallic phases (i.e., the low temperature ferromagnetic and the colossal magnetoresistant phase under a magnetic field of 7 T). Robust signatures of the metal-insulator transition are identified in the momentum density for the paramagnetic phase above the Curie temperature. We interpret our results as providing direct evidence for the transition from the metalliclike to the admixed ionic-covalent bonding accompanying the magnetic transition. The number of electrons involved in this phase …
Role Of Oxygen Electrons In The Metal-Insulator Transition In The Magnetoresistive Oxide La2-2xsr1+2xmn2o7 Probed By Compton Scattering, B. Barbiellini, A. Koizumi, P. E. Mijnarends, W. Al-Sawai, Hsin Lin, T. Nagao, K. Hirota, M. Itou, Y. Sakurai, A. Bansil
Role Of Oxygen Electrons In The Metal-Insulator Transition In The Magnetoresistive Oxide La2-2xsr1+2xmn2o7 Probed By Compton Scattering, B. Barbiellini, A. Koizumi, P. E. Mijnarends, W. Al-Sawai, Hsin Lin, T. Nagao, K. Hirota, M. Itou, Y. Sakurai, A. Bansil
Arun Bansil
We have studied the [100]-[110] anisotropy of the Compton profile in the bilayer manganite. Quantitative agreement is found between theory and experiment with respect to the anisotropy in the two metallic phases (i.e., the low temperature ferromagnetic and the colossal magnetoresistant phase under a magnetic field of 7 T). Robust signatures of the metal-insulator transition are identified in the momentum density for the paramagnetic phase above the Curie temperature. We interpret our results as providing direct evidence for the transition from the metalliclike to the admixed ionic-covalent bonding accompanying the magnetic transition. The number of electrons involved in this phase …
A Structural, Magnetic, And Mössbauer Spectral Study Of The Tbco₄₋ₓfeₓb Compounds With X=0, 1, And 2, Herv´ Mayot, Olivier Isnard, Fernande Grandjean, Gary J. Long
A Structural, Magnetic, And Mössbauer Spectral Study Of The Tbco₄₋ₓfeₓb Compounds With X=0, 1, And 2, Herv´ Mayot, Olivier Isnard, Fernande Grandjean, Gary J. Long
Chemistry Faculty Research & Creative Works
The TbCo4-x Fex B compounds with x=0, 1, and 2 have been investigated by x-ray and neutron diffraction, magnetic measurements, and iron-57 Mössbauer spectroscopy. The substitution of cobalt by iron induces both an anisotropic increase in the unit-cell volume and a large increase of approximately 250 K in the Curie temperature; the 4.2 K magnetization decreases continuously with increasing iron content. The powder neutron diffraction patterns and the Mössbauer spectra of the TbCo4-x Fex B compounds reveal a strong preferential substitution of iron for cobalt on the 2c site, small transition metal magnetic moments of approximately …
Magnetic Entropy Change Of V Substituted Ni–Mn–Ga Heusler Alloy, S G. Min, L Malkinski, Y D. Zhang, S C. Yu, K W. Lee, Y C. Kim
Magnetic Entropy Change Of V Substituted Ni–Mn–Ga Heusler Alloy, S G. Min, L Malkinski, Y D. Zhang, S C. Yu, K W. Lee, Y C. Kim
Physics Faculty Publications
The magnetization behaviors have been analyzed for Ni54Mn21−xVxGa25 (x = 0,2,4) alloys which were prepared by conventional arc melting method in argon atmosphere. The Curie temperature TC was found to be 325, 300, and 265 K and the austenitic transition temperature TA on heating was found to be 315, 217, and 124 K for x = 0, 2, and 4, respectively. The magnetic characteristics were performed with a Quantum Design superconducting quantum interference device magnetometer in the field of up to 20 kOe. A large magnetic entropy change Δ …
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Thermal Effects On Domain Orientation Of Tetragonal Piezoelectrics Studied By In Situ X-Ray Diffraction, Wonyoung Chang, Alexander H. King, Keith J. Bowman
Alexander H. King
Thermal effects on domain orientation in tetragonal lead zirconate titanate (PZT) and lead titanate (PT) have been investigated by using in situ x-ray diffraction with an area detector. In the case of a soft PZT, it is found that the texture parameter called multiples of a random distribution (MRD) initially increases with temperature up to approximately 100 °C and then falls to unity at temperatures approaching the Curie temperature, whereas the MRD of hard PZT and PT initially undergoes a smaller increase or no change. The relationship between the mechanical strain energy and domain wall mobility with temperature is discussed.
Structure, Magnetic, And Transport Properties Of Ti-Substituted La₀.₇Sr₀.₃Mno₃, M. S. Kim, Jinbo Yang, Qingsheng Cai, X.-D. Zhou, William Joseph James, William B. Yelon, D. Buddhikot, Satish K. Malik, Paul Ernest Parris
Structure, Magnetic, And Transport Properties Of Ti-Substituted La₀.₇Sr₀.₃Mno₃, M. S. Kim, Jinbo Yang, Qingsheng Cai, X.-D. Zhou, William Joseph James, William B. Yelon, D. Buddhikot, Satish K. Malik, Paul Ernest Parris
Materials Science and Engineering Faculty Research & Creative Works
Ti-substituted perovskites La0.7Sr0.3Mn1-xTixO3 with 0 ≤ x ≤ 0.20, were investigated by neutron diffraction, magnetization, electric resistivity, and magnetoresistance (MR) measurements. All samples show a rhombohedral structure (space group R3c) from 10 K to room temperature. At room temperature, the cell parameters a,c and the unit cell volume increase with increasing Ti content. However, at 10 K, the cell parameter a has a maximum value for x = 0.10, and decreases for x > 0.10, while the unit cell volume remains nearly constant for x > 0.10. The average (Mn,Ti)-O bond length increases …