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Engineering Physics

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Materials science

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Full-Text Articles in Physics

Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim Jan 2020

Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim

Physics Faculty Publications

We investigate thermodynamic properties of FeSe under in-plane magnetic fields using torque magnetometry, specific heat, and magnetocaloric measurements. Below the upper critical field Hc2, we observed the field induced anomalies at H1 ∼ 15 T and H2 ∼ 22 T near H ∥ ab and below a characteristic temperature T* ∼ 2 K. The transition magnetic fields H1 and H2 exhibit negligible dependence on both temperature and field orientation. This contrasts to the strong temperature and angle dependence of Hc2, suggesting that these anomalies are attributed to the field induced phase transitions, …


Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji Jan 2019

Charge Storage In Wo³ Polymorphs And Their Application As Supercapacitor Electrode Material, Vaibhav Lokhande, Abhishek Lokhande, Gon Namkoong, Jin Hyeok Kim, Taeksoo Ji

Electrical & Computer Engineering Faculty Publications

Tungsten oxide is a versatile material with different applications. It has many polymorphs with varying performance in energy storage application. We report simple and facile way to synthesize four phases of tungsten oxide from same precursor materials only by changing the pH and temperature values. Monoclinic, hexagonal, orthorhombic and tetragonal phase obtained, were analyzed and tested for supercapacitor application. The electrochemical analysis of four phases indicates that the hexagonal phase is best-suited electrode material for supercapacitor. The hexagonal phase exhibits higher specific capacitance (377.5 Fg-1 at 2 mVs-1), higher surface capacitive contribution (75%), better stability and rate …


Anisotropic Thermodynamic And Transport Properties Of Single-Crystalline Cakfe4As4, W. R. Meier, T. Kong, U. S. Kaluarachchi, V. Taufour, N. H. Jo, G. Drachuck, A. E. Böhmer, S. M. Saunders, A. Sapkota, A. Kreyssig, M. A. Tanatar, R. Prozorov, A. I. Goldman, Fedor F. Balakirev, Alex Gurevich, S. L. Bud'ko, P. C. Canfield Jan 2016

Anisotropic Thermodynamic And Transport Properties Of Single-Crystalline Cakfe4As4, W. R. Meier, T. Kong, U. S. Kaluarachchi, V. Taufour, N. H. Jo, G. Drachuck, A. E. Böhmer, S. M. Saunders, A. Sapkota, A. Kreyssig, M. A. Tanatar, R. Prozorov, A. I. Goldman, Fedor F. Balakirev, Alex Gurevich, S. L. Bud'ko, P. C. Canfield

Physics Faculty Publications

Single-crystalline, single-phase CaKFe4As4 has been grown out of a high-temperature, quaternary melt. Temperature-dependent measurements of x-ray diffraction, anisotropic electrical resistivity, elastoresistivity, thermoelectric power, Hall effect, magnetization, and specific heat, combined with field-dependent measurements of electrical resistivity and field and pressure-dependent measurements of magnetization indicate that CaKFe4As4 is an ordered, stoichiometric, Fe-based superconductor with a superconducting critical temperature, Tc = 35.0 ± 0.2 K. Other than superconductivity, there is no indication of any other phase transition for 1.8K ≤ T ≤ 300 K. All of these thermodynamic and transport data reveal striking similarities to …