Reversible strain effect in La_(0.7)Sr_(0.3)MnO_3 step edge junctions

摘要

The spin-polarized electric transport in ferromagnetic La_(0.7)Sr_(0.3)MnO_3 films on piezoelectric substrates with etched steps has been investigated. The Pb(Mg_(1/3)Nb_(2/3))_(0.72)Ti_(0.28)O_3 substrate is strained reversibly by application of electric voltage. This includes strain control in film junctions formed at step edges. The film resistance (R) is very sensitive to both strain and magnetic field in a wide temperature range, 30 K < T < 300 K, in contrast to the behavior of step-free films. Both R and magnetoresistance decrease (increase) significantly upon in-plane compression (expansion). In this way, strain is introduced as variable parameter for experiments on step edge grain boundaries.