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

采用直流磁控溅射法在熔融石英玻璃上沉积了Fe-Pd薄膜。当电弧熔化和均化Fe-30at时。以%Pd合金圆盘为靶材，制备的Fe-Pd薄膜含有约24at。%PD。然后通过在目标上添加Pd丝来修改目标配置，以便在精度为1at的范围内定制具有所需Pd含量的薄膜。%PD。制备了四种合金成分的Fe-Pd薄膜，并用X射线衍射仪、扫描电子显微镜和能谱分析技术对其进行了分析。与大块合金样品类似，Fe-28~31.3at.%Pd薄膜在90 0℃下经冷水淬火后，在热循环过程中也表现出由面心立方向面心立方转变的热弹性马氏体转变。薄膜具有铁磁性，并且在加热和冷却时表现出双向SM效应。上述两种方法都不利于厚膜的沉积，因为在溅射过程中，合金靶上的Pd线需要变薄。为此，我们搭建了一套双源磁控溅射装置，并成功地沉积了成分可控的较厚薄膜。发现较厚薄膜的马氏体相变行为与合金靶沉积的薄膜基本相同。

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.