Local characterization of superconductivity in BaFe2(As1-xPx)2

We use magnetic force microscopy (MFM) to characterize superconductivity across the superconducting dome in BaFe2(As1-xPx)(2), a pnictide with a peak in the penetration depth (lambda(ab)) at optimal doping (x(opt)), as shown in sample-wide measurements. Our local measurements show a peak at x(opt) and a T-C vs lambda(-2)(ab) dependence similar on both sides of x(opt). Near the underdoped edge of the dome lambda(ab) increases sharply, suggesting that superconductivity competes with another phase. Indeed, MFM vortex imaging shows correlated defects parallel to twin boundaries only in underdoped samples and not for x >= x(opt).