Voltage-controllable Magnetoelectrics: New Thin Film Material and Characterization
Thesis Defense
2:30 pm
Jorgensen Hall Room: 136
Junlei Wang
Advisor: Professor Christian Binek
?
Abstract
A promising path towards scalable, non-volatile, ultra-low power memory and logical devices with high switching speed utilizes the magnetoelectric effect in antiferromagnetic insulators as fundamental building block. The resulting voltage-controlled spintronics could either complement or become a suitable replacement for today’s electronics including complementary metal-oxide-semiconductor devices. My thesis aims at advancing the understanding of magnetoelectric antiferromagnets. Of particular interest is the voltage-controlled switching of the antiferromagnetic order parameter. In my presentation, I lay out my experimental investigations which enable progress in fabrication of magnetoelectric thin films of the antiferromagnetic material Fe2TeO6, which hitherto has not been investigated in thin film geometry. In addition, I present a new table-top magneto-optical setup, which allows simultaneous measurements of electric field induced Faraday and Kerr effects. The setup is used to investigate the frequency dependence of the electric field induced Faraday effect. The theoretically predicted dispersion of the electric field induced Faraday rotation is experimentally confirmed. The dispersion is utilized to tune the probing light frequency into the regime where the specific Faraday rotation is directly proportional to the antiferromagnetic order parameter. Thus, the historically challenging problem of monitoring the reversal of the antiferromagnetic order parameter is solved for the particular class of magnetoelectric antiferromagnets.
Advisor: Professor Christian Binek
?
Abstract
A promising path towards scalable, non-volatile, ultra-low power memory and logical devices with high switching speed utilizes the magnetoelectric effect in antiferromagnetic insulators as fundamental building block. The resulting voltage-controlled spintronics could either complement or become a suitable replacement for today’s electronics including complementary metal-oxide-semiconductor devices. My thesis aims at advancing the understanding of magnetoelectric antiferromagnets. Of particular interest is the voltage-controlled switching of the antiferromagnetic order parameter. In my presentation, I lay out my experimental investigations which enable progress in fabrication of magnetoelectric thin films of the antiferromagnetic material Fe2TeO6, which hitherto has not been investigated in thin film geometry. In addition, I present a new table-top magneto-optical setup, which allows simultaneous measurements of electric field induced Faraday and Kerr effects. The setup is used to investigate the frequency dependence of the electric field induced Faraday effect. The theoretically predicted dispersion of the electric field induced Faraday rotation is experimentally confirmed. The dispersion is utilized to tune the probing light frequency into the regime where the specific Faraday rotation is directly proportional to the antiferromagnetic order parameter. Thus, the historically challenging problem of monitoring the reversal of the antiferromagnetic order parameter is solved for the particular class of magnetoelectric antiferromagnets.