TANMS Fabricates New Magnetoelectric Coupling Type for Dynamic Magnetic Control

Achievement date: 
2017
Outcome/accomplishment: 

A new type of magnetoelectric coupling has been fabricated and validated by researchers at the NSF-funded Nanosystems Engineering Research Center (NERC) for Translational Applications of Nanoscale Multiferroic Systems (TANMS), headquartered at the University of California in Los Angeles (UCLA). The work enables a fundamentally new magnetoelectric coupling mechanism that allows for dynamic control of magnetism by tuning the way small magnetic domains interact.

Impact/benefits: 

New types of magnetoelectric coupling have great potential to enable more streamlined magnetic switching mechanisms in future applications. By applying a voltage, the ferroelectric used in the experimental magnetoelectric composites developed at TANMS could directly alter the local nanoscale environment and potentially allow for control of magnetism through a robust, low power mechanism.Because only two components are necessary, this research has the potential to drastically simplify future technology designs, leading to smaller, faster, more energy efficient devices.

Explanation/Background: 

Theoretical modeling of the new coupling type, first developed at California State University, Northridge, proposed that: interactions between neighboring nanomagnets would determine the overall magnetic behavior of the system; and, that this communication between neighbors can be controlled by changing their local surrounding environment in a switchable manner.

To validate these theories, TANMS researchers at UCLA fabricated experimental magnetoelectric composite samples; then tested how local environmental changes may affect existing multiferroic testbeds.The experimental results revealed three distinct magnetic behaviors, each determined by altering the local environment around nickel metal nanomagnets. Fits between the experimental data and theoretical models provided strong validation for the novel magnetoelectric coupling mechanism. A key finding confirms that exchange coupling is predictably dependent on the dielectric environment. Spin reorientation in single domain magnetic nanocrystals is in part determined by exchange coupling between closely spaced nanocrystals in materials where the spacing is approximately 1 nanometer (nm) or less. As a result, a ferroelectric (FE) can be used to change the dielectric environment in a switchable manner, either by transitioning the FE through its Curie temperature, or by applying an electric field to move the FE through its Curie temperature. In either case, the result is more dynamic control of the exchange coupling that governs the magnetic spins.