Upper critical field of Nb/Pd1-xFex/Nb triple layers

The parallel upper critical field B-c2 parallel to(T) of Nb/Pd1-xFex/Nb tri ple layers exhibits with increasing interlayer thickness and/or increasing Fe concentration x a transition from two-dimensional (2D) behavior of the w hole sandwich, where the Nb films are coupled across the ferromagnetic inte rlayer, to a 2D behavior of decoupled Nb films. The interlayer thickness d( c), above which no transition is observed drops precipitously from similar to 100 to 15 Angstrom around x approximate to 0.1 and remains nearly consta nt up to x = 1. This change is most probably associated with a change of th e interlayer from paramagnetic to ferromagnetic order with increasing x. (C ) 2000 Elsevier Science B.V. All rights reserved.