Coercive Field Enhancement in Microstructured (La_1-yPr_y)_1-xCa_xMnO₃ thin films

(La_1-yPr_y)_1-xCa_xMnO₃ (LPCMO) is a perovskite material with complex electronic and magnetic behaviors because of phase competition between its ferromagnetic metallic (FMM) phase and charged order insulating (COI) phase. LPCMO thin films also exhibit unique magnet behavior due to the additional effects of substrate-induced strain such as single-domain to multi-domain transition as a function of temperature. LPCMO thin films were deposited on NdGaO₃ (NGO) substrates using pulsed laser deposition. These thin films were then patterned into an array of 100 µm squares using photolithography. We observed that the coercive field increased by a factor of about 4 due to the patterned microstructure. This coercive field enhancement is due to magnetic interactions between the isolated LPCMO regions mediated by the paramagnetic NGO substrate. We will also discuss the effects on the coercive field due to increasing the gap between the patterned squares in the array.