Neural stimulators can be used for the management of neurological disorders such as Parkinson's disease via electrical stimulation of neurons. However, implanted neural devices are large, complex, and invasive. Instead, neural devices that are nanoscale, injectable, and wireless can provide a less invasive approach to neurostimulation, but wireless power transfer at the nanoscale is a challenge. 
 
Magnetoelectric nanoparticles (MENPs) enable wireless power transfer to the brain via conversion of an applied magnetic field into an electric field. These ferromagnetic MENPs constitute a piezoelectric component and magnetostrictive component which are coupled by a common interface to generate magnetic-to-electric coupling via strain translation. 
 
Tuning the properties of the magnetostrictive component enables tuning of the translated strain to the piezoelectric, and therefore controls the output signal of these nanoelectrodes.
 
Here we show the synthesis of the magnetostrictive core via a coprecipitation method, where the properties have been tuned by varying three synthesis parameters: the concentration of the coprecipitation agent, and the time and temperature of the calcination process.
 
XRD measurements showed that higher calcination temperatures gave rise to a more prone crystallization and confirmed that cobalt ferrite crystallized in the cubic spinel structure. VSM measurements showed that the coercivity and magnetic saturation could be tuned by varying the synthesis parameters. Additionally, the change in the magnetic properties leads to a change in the magnetoelectric properties. 
 
Controlling the magnetic properties can lead to tunable magnetoelectric properties and finally lead to multiplexed neural stimulation.
 
Wirelessly powered and injectable MENPs are a promising technology that could one day provide a less invasive approach to the treatment of neurological disorders. This work shows that we can use basic chemistry to control the magnetostrictive, and thereby magnetoelectric, properties of these materials. The methods discussed herein demonstrate a facile approach to tune the signal-response of wireless nanoelectrodes.