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From Wikipedia, the free encyclopedia
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In chemistry, oxypnictides are a class of materials including oxygen, a pnictogen (group-V, especially phosphorus and arsenic) and one or more other elements.
The interest in this group of compounds results from the superconducting properties which were discovered 2006[1] and 2008[2].[3]
Structure
For example LaOFeP has a layered structure with layers of La3+02- and Fe2+P3-.[1]
Superconductor
The first superconducting iron oxypnictide was discovered in 2006, based on phosphorus.[1] A drastic increase in the critical temperature was achieved when phosphorus was substituted by arsenic[2]. This discovery boosted the search for similar compounds, like the search for cuprate-based superconductors after their discovery in 1986.
Some found in 2008 to be high temperature superconductors (at 43 K) of composition ReOTmPn where Re is a rare earth, Tm is a transition metal and Pn is from group-V eg As.[4]
Tests at up to 45 Tesla[5] [6]suggest the upper critical field of LaFeAsO0.89F0.11 may be around 64 Tesla.