Mechanical stress in FM/NM/FM trilayers grown on flexible polyimide
29/05/2012 17:21
Data: 29/05/2012
Título: Mechanical stress in FM/NM/FM trilayers grown on flexible polyimide
Autora: Drª. Thatyara Freire
Resumo: Mechanical strain and stress are important physical parameters in applications such as shape, strain, and force monitoring. Highly sensitive strain gauges can be developed based on tunnel magnetoresistance (TMR) or giant magnetoresistance (GMR) effects combined with the inverse magnetostriction (Villari effect). Static stresses were applied to a series of magnetic multilayers to observe the changes in their magnetic properties. The objective is to investigate the influence of mechanical strain on the magnetization and consequently on the electrical resistance of the trilayers systems. All FM/NM/FM trilayers were grown on polyamide substrates (0,127 mm) by dc magnetron sputtering at a base pressure of 3,0 x 10-8 mbar and a working argon pressure of 5,0 x 10-3 mbar. The thickness of the NM interlayer was chosen to ensure a most strong antiferromagnetic exchange coupling between adjacent FM layers. Vibrating sample magnetometry (VSM) and four point resistance measurements at room temperature are used to determine the magnetic properties of the samples under mechanical stress.