Metamagnetic transition and spin memory effect in epitaxial Gd1-xCaxMnO3(0≤x≤1) thin films

Epitaxial Gd1-xCaxMnO30≤x≤1 thin films were prepared by pulsed laser deposition (PLD) on SrTiO3 substrate and their magnetic properties were investigated. Similar in the bulk samples, the field cooled (FC) and zero field cooled (ZFC) curves of the films show a hump and negative value of magnetization at low temperature which could be attributed to the magnetic moments of Gd ions which order in the opposite direction of Mn ions. However, the magnetic hysteresis loop of the films is different from that of bulk samples. In low doped concentrations, 0.1≤x≤0.3, a metamagnetic transition occurs in low applied field at low temperature. At Ca concentration, 0.4≤x≤0.7, the magnetization versus external magnetic field behaves like a soft ferromagnet. In high Ca concentrations, x=0.8 and x=1 demonstrate antiferromagnetic transition in ZFC curve and thus the magnetization shows antiferromagnetic behavior at low temperature. In contrast, x=0.9 displays soft ferromagnetic hysteresis loop with evidence of training effect. It could be associated with the cluster glass peak in ZFC curve for this film.