Exchange-coupling-induced antiferromagnetic-ferromagnetic transition in Pr_(0.5)Ca_(0.5)MnO_3/La_(0.5)Ca_(0.5)MnO_3 superlattices

摘要

Superlattices built from two antiferromagnetic (AFM), charge- and/or orbital-order compounds, Pr_(0.5)Ca_(0.5)MnO_3 and La_(0.5)Ca_(0.5)Mno_3, were studied as the thickness of La_(0.5)Ca_(0.5)MnO_3 (LCMO) varied. High-structural-quality thin films were obtained on LaAlO_3 substrates using the pulsed-laser-deposition technique. An antiferromagnetic-to-ferromagnetic transition, in addition to an enhancement of the coercivity, was observed as the LCMO-layer thickness increased. The small shift in the origin of the field-cooled hysteresis loop along the field axis indicates the presence of ferromagnetic and antiferromagnetic phases in the superlattices. We attribute these features to the AFM spin fluctuations at the Pr_(0.5)Ca_(0.5)MnO_3/La_(0.5)Ca_(0.5)MnO_3 interfaces resulting from the strain effects.