电场调制FeCoSi/PZT驱动器磁性研究

Study on the Magnetism of Electric-Field Modulated FeCoSi/PZT Actuator

采用射频磁控共溅射方法在玻璃衬底上制备了具有面内单轴各向异性的FeCoSi磁性薄膜。使FeCoSi磁性薄膜初始易磁化方向(称为初始易轴)与PZT驱动器应力方向(长轴方向)平行进行粘接得到FeCoSi/PZT驱动器异质结,用于研究通过电场来调制磁性薄膜的磁矩转动及各向异性场的场强,并利用微聚焦磁光克尔效应测量了不同电压下FeCoSi磁性薄膜初始难磁化方向(称为初始难轴)的磁滞回线。结果表明:当给PZT驱动器施加正电压时,异质结在张应力的作用下薄膜的易磁化方向保持不变,但各向异性场变大,各向异性场随电压的变化关系约为0.12Oe/V,从而实现了电场对各向异性场场强的调制;当给PZT驱动器施加负电压时,异质结在压应力的作用下使磁矩偏离初始易轴,而磁矩从初始易轴方向转到初始难轴方向所需施加的电压为-80V,从而实现了电场对磁性薄膜磁矩转动的调制。文中实现的通过电场对FeCoSi磁性薄膜磁矩转动和各向异性场的调制有望在低功耗微波器件中得到应用。

FeCoSi magnetic thin film with in-plane uniaxial anisotropy was fabricated on glass substrate by RF magnetron co-sputtering.A FeCoSi/PZT actuator heterojunction was obtained through a parallel bonding with magnetic film＇s original easy-magnitization axis along the PZT actuator＇s length direction,which is the main direction for stress generating,and the heterojunction was used to investigate the magnetic moment switching of electric-field modulated magnetic film and the intensity of anisotropic field.The hysteresis loops of FeCoSi film in hardmagnitization axis direction were measured under various voltages via micro-focus magneto-optical Kerr effect.Results showed that when a positive voltage was applied to the PZT actuator,the magnetic moment along the original easy axis maintained unchanged if the heterojunction was under a tensile stress,and the intensity of anisotropic field increased with the tensile stress at a rate of around 0.12Oe/V.While under negative voltage,the magnetic moment deviated from the original easy axis direction under the compressive stress.The switching of magnetic moment from original easy axis direction to hard axis direction could be achieved under a negative voltage of-80V.The electric-field controlled magnetic moment switching and anisotropic field modulationmay get potential applications in low-power microwave devices.