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Articles 1 - 8 of 8
Full-Text Articles in Physics
Complex Electronic States In Double-Layered Ruthenates (Sr1−Xcax)3ru2o7, Zhe Qu, Jin Peng, David Fobes, Leonard Spinu, Zhiqiang Mao
Complex Electronic States In Double-Layered Ruthenates (Sr1−Xcax)3ru2o7, Zhe Qu, Jin Peng, David Fobes, Leonard Spinu, Zhiqiang Mao
Physics Faculty Publications
The magnetic ground state of (Sr1−xCax)3Ru2O7 (0≤x≤1) is complex, ranging from an itinerant metamagnetic state (0≤x<0.08) to an unusual heavy-mass nearly ferromagnetic (FM) state (0.08<x<0.4), and finally to an antiferromagnetic (AFM) state (0.4≤x≤1). In this report we elucidate the electronic properties for these magnetic states, and show that the electronic and magnetic properties are strongly coupled in this system. The electronic ground state evolves from an AFM quasi-two-dimensional metal for x=1.0 to an Anderson localized state for 0.4≤x<1.0 (the AFM region). When the magnetic state undergoes a transition from the AFM to the nearly FM state, the electronic ground state switches to a weakly localized state induced by magnetic scattering for 0.25≤x<0.4, and then to a magnetic metallic state with the in-plane resistivity ρab∝Tα (α>2) for 0.08<x<0.25. The system eventually transforms into a Fermi-liquid ground state when the magnetic ground state enters the itinerant metamagnetic state for x<0.08. When x approaches the critical composition (x∼0.08), …
Morphology, Magnetic And Dynamic Properties Of Artificial Structures Assembled By Acoustic Vibrations, K B. Paul, L Malkinski
Morphology, Magnetic And Dynamic Properties Of Artificial Structures Assembled By Acoustic Vibrations, K B. Paul, L Malkinski
Physics Faculty Publications
Cobalt micromagnetic particles with an average size of ≈ 1.6 μm and varying total mass of the powder were assembled on patterned media with perpendicular magnetization by acoustic vibrations onto designed shapes reflecting the primary material. The replicas were studied with scanning electron microscopy, vibrating sample magnetometry, and ferromagnetic resonance spectroscopy. Their properties were significantly influenced by the shape anisotropy induced through the parent molds. A tendency in the development of the physical characteristics of the replicas was observed as their geometrical parameters changed.
Charge-Carrier Localization Induced By Excess Fe In The Superconductor Fe1+Yte1−Xsex, T J. Liu, X Ke, B Qian, J Hu, D Fobes, E K. Vehstedt, H Pham, J H. Yang, M H. Fang, L Spinu, P Schiffer, Y Liu, Z Q. Mao
Charge-Carrier Localization Induced By Excess Fe In The Superconductor Fe1+Yte1−Xsex, T J. Liu, X Ke, B Qian, J Hu, D Fobes, E K. Vehstedt, H Pham, J H. Yang, M H. Fang, L Spinu, P Schiffer, Y Liu, Z Q. Mao
Physics Faculty Publications
We have investigated the effect of Fe nonstoichiometry on properties of the Fe1+y(Te,Se) superconductor system by means of resistivity, Hall coefficient, magnetic susceptibility, and specific-heat measurements. We find that the excess Fe at interstitial sites of the (Te, Se) layers not only suppresses superconductivity but also results in a weakly localized electronic state. We argue that these effects originate from the magnetic coupling between the excess Fe and the adjacent Fe square-planar sheets, which favors a short-range magnetic order.
Dynamic Critical Curve Of A Synthetic Antiferromagnet, Huy Pham, Dorin Cimpoesu, Andrei-Valentin Plamada, Alexandru Stancu, Leonard Spinu
Dynamic Critical Curve Of A Synthetic Antiferromagnet, Huy Pham, Dorin Cimpoesu, Andrei-Valentin Plamada, Alexandru Stancu, Leonard Spinu
Physics Faculty Publications
We have investigated the effect of Fe nonstoichiometry on properties of the Fe1+y(Te,Se) superconductor system by means of resistivity, Hall coefficient, magnetic susceptibility, and specific-heat measurements. We find that the excess Fe at interstitial sites of the (Te, Se) layers not only suppresses superconductivity but also results in a weakly localized electronic state. We argue that these effects originate from the magnetic coupling between the excess Fe and the adjacent Fe square-planar sheets, which favors a short-range magnetic order.
Friction On The Microscale, K B. Paul, L Malkinski
Friction On The Microscale, K B. Paul, L Malkinski
Physics Faculty Publications
A new method is presented for measurements of friction of microsized particles on surfaces. Specifically in this work, the particles are alumina with diameters between ≈ 1 and 50 μm and the surfaces are InP, Si, and Cr. Friction is analyzed, its components are determined, and the friction coefficients are estimated from the experimental results. The technique and the specific instrument allow measurements of coefficients of friction for spherical particles with radii as small as 1 μm. For smaller sizes, the instrument needs to be modified by using a more powerful power supply, actuator with extended frequency and …
Structural, Magnetic, And Electronic Transport Properties Of (Sr0.9ca0.1)3ru2o7 Single Crystal, Bin Qian, Zhe Qu, Jin Peng, Tijang Liu, Xiaoshan Wu, L Spinu, Z Q. Mao
Structural, Magnetic, And Electronic Transport Properties Of (Sr0.9ca0.1)3ru2o7 Single Crystal, Bin Qian, Zhe Qu, Jin Peng, Tijang Liu, Xiaoshan Wu, L Spinu, Z Q. Mao
Physics Faculty Publications
We have studied the structural, magnetic, and electronic transport properties of (Sr0.9Ca0.1)3Ru2O7 using single crystals grown by a floating-zone technique. The structure analysis by Rietveld refinements reveals that the Ca substitution for Sr intensifies the structure distortion; the rotation angle of the RuO6 octahedron increases. This structure change tunes magnetic and transport properties dramatically. The magnetic ground state switches from an itinerant metamagnetic state for Sr3Ru2O7 to a nearly ferromagnetic state for (Sr0.9Ca0.1)3Ru2O7. The Fermi …
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 …
Tunable (Δπ, Δπ)-Type Antiferromagnetic Order In Α-Fe(Te,Se) Superconductors, Wei Bao, Y Qiu, Q Huang, M A. Green, P Zajdel, M R. Fitzsimmons, M Zhernenkov, S Chang, M Fang, B Qian, Jinhu Yang, H M. Pham, L Spinu, Z Q. Mao
Tunable (Δπ, Δπ)-Type Antiferromagnetic Order In Α-Fe(Te,Se) Superconductors, Wei Bao, Y Qiu, Q Huang, M A. Green, P Zajdel, M R. Fitzsimmons, M Zhernenkov, S Chang, M Fang, B Qian, Jinhu Yang, H M. Pham, L Spinu, Z Q. Mao
Physics Faculty Publications
The new α-Fe(Te,Se) superconductors share the common iron building block and ferminology with the LaFeAsO and BaFe2As2 families of superconductors. In contrast with the predicted commensurate spin-density-wave order at the nesting wave vector (π, 0), a completely different magnetic order with a composition tunable propagation vector (δπ, δπ) was determined for the parent compound Fe1+yTe in this powder and single-crystal neutron diffraction study. The new antiferromagnetic order survives as a short-range one even in the highest TC sample. An alternative to the prevailing nesting Fermi surface mechanism is required to understand the latest family …