Ferromagnetism Induced in UCoAl by Uniaxial Pressure |
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Authors: | V Sechovský AV Andreev Y Ishii M Kosaka Y Uwatoko |
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Institution: | 1. Department of Electronic Structures , Charles University , Ke Karlovu 5, Prague 2 , 121 16 , The Czech Republic Fax:;2. AS CR , Institute of Physics , Na Slovance 2, Prague 8 , 182 21 , The Czech Republic;3. Saitama University , 255 Shimo-okubo, Urawa, Saitama , 338-8570 , Japan |
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Abstract: | UCoAl exhibits attributes of an itinerant 5f-electron metamagnet. It is paramagnetic down to lowest temperatures but the c -axis susceptibility shows a maximum around T max , 20 K. When a field larger than B c , 0.6 T is applied along the c -axis of hexagonal structure a ferromagnetic ordering of U moments is induced at low temperatures. The critical parameters T max and B c are sensitive to alloying and hydrostatic pressure. In the latter case values of both, T max and B c , are increasing with increasing pressure, i.e. metamagnetism is suppressed towards a conventional paramagnetism. We report on results of an experiment with a c -axis uniaxial pressure, which has an opposite influence on T max and B c leading to ferromagnetism in zero field. A scenario of the physics of UCoAl is presented accounting for effects of hydrostatic- and uniaxial-pressure on the lattice and consequences in the 5f-electron delocalization and anisotropy of hybridization-mediated exchange interactions. |
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Keywords: | Ucoal Itinerant Electron Metamagnetism Hydrostatic Pressure Uniaxial Pressure Ferromagnetism 5f-ligand Hybridization |
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