Highly Flexible Magnetoelectronic Device Integrated With Embedded Ag Nanoparticle Electrode

A flexible magnetoresistance (MR) device is fabricated through the hybrid process of embedding an Ag nanoparticle electrode by thermal imprinting and magnetic multilayer sensor element by sputtering on a polyethylene naphthalate (PEN) substrate. The MR signal profiles for a ring type sensor deposited on the PEN substrate show typical anti-symmetric curves centered for the field H=0, and the maximum signal and its field sensitivity are nearly the same as those of sensors deposited on Si and glass substrates. The root mean square (rms) roughnesses and magnetic properties of magnetic thin film deposited on the different substrates show that H_ex was decreased with increasing roughness. Further, MR change with temperature had no significant effect on the sensor performance. The stability of Au electrode and Ag paste electrode were compared during the bending of MR sensor, revealing the cracking of Au electrode above 45°. However, Ag paste electrode was stable up to 90°. The field sensitivity of the MR signal for the full range of fields is inversely proportional to the effective anisotropy field, which is the sum of exchange-bias and stress-induced anisotropy fields. As a whole, the field sensitivity of MR signal depends on bending stress at the sensor position.