Figure 5. Muon spin rotation signal.

Time dependence of the muon decay asymmetry (proportional to the polarization) for muons implanted at 12.5 keV in the central underdoped layer (T_c′≲5 K) of the trilayer structure La_1.84Sr_0.16CuO₄ (46 nm)/La_1.94Sr_0.06CuO₄ (46 nm)/La_1.84Sr_0.16CuO₄ (46 nm). An external magnetic field of 9.5 mT was applied parallel to the ab planes and to the interface (Meissner geometry). The signal at 40 K (black) represents the muon spin precession in the external field. At 9.5 K (red), well above T_c′, the lower precession frequency (proportional to the average local field) reflects the presence of diamagnetism in the barrier. Error bars indicate the statistical errors of the data, curves are fits to the data (see text for details).