Deposition of ferromagnetic shape memory alloy thin films by dc unbalanced magnetron sputtering

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Fe-Pd films were deposited onto fused quartz glasses by dc magnetron sputtering. When an arc-melted and homogenized Fe-30 at. %Pd alloy disk was used as a target, Fe-Pd films fabricated were found to contain about 24 at. % Pd. The target configuration was then modified by adding wires of Pd on the target so as to tailor films with desired Pd content within an accuracy of 1 at. %Pd. Fe-Pd films with four alloy compositions were fabricated and analyzed by XRD, SEM and EDX techniques for as-deposited and heat-treated conditions. Similar to bulk alloy specimens, the Fe-28〜31.3 at.%Pd films also showed a thermoelastic fcc-to-fct martensite transformation during thermal cycling after annealing at 900 ℃ followed by iced water quenching. The films were found to be ferromagnetic and show two-way SM effects upon heating and cooling.Above mentioned method has a disadvantage for depositing thick films because the Pd wires arranged on the alloy target should be thinning during sputtering. Therefore, we constructed a dual source magnetron sputtering apparatus, and succeeded in depositing the thicker films with controlled composition. The martensite transformation behavior of thicker films were found to be nearly the same as the films deposited from alloy target.