]>The Phenomenology of Iron Pnictides Superconductors Explained in the Framework of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi>s</mml:mi></mml:math>-Wave Three-Band Eliashberg Theory : Figure 6
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Figure 6: Calculated temperature dependence of the penetration depth ( [ 𝜆 ( 𝑇 ) / 𝜆 ( 𝑇 = 1 K ) ] 2 ) for LaFeAsO 0 . 9 F 0 . 1 ( 𝑇 𝑐 = 2 7  K, red solid line), Ba 0 . 6 K 0 . 4 Fe 2 As 2 ( 𝑇 𝑐 = 3 7  K, dash blue line), and for SmFeAsO 0 . 8 F 0 . 2 ( 𝑇 𝑐 = 5 2  K, green dash-dot line). The insert shows the behaviour of [ 𝜆 ( 𝑇 ) − 𝜆 ( 𝑇 = 1 K ) ] / 𝜆 ( 𝑇 = 1 K ) obtained by solution of Eliashberg equations: red circles for LaFeAsO 0 . 9 F 0 . 1 , dark blue triangle for Ba 0 . 6 K 0 . 4 Fe 2 As 2 , green squares for SmFeAsO 0 . 8 F 0 . 2 . The lines are the third-order polynomial fits.