Powerful and Tunable THz Emitters Based on the Fe/Pt Magnetic Heterostructure

TL;DR

This paper demonstrates that Fe/Pt magnetic heterostructures can serve as powerful, tunable terahertz emitters, with emission strength and spectrum adjustable via layer thickness and magnetic field, promising new device applications.

Contribution

It introduces a novel approach to creating tunable THz emitters using Fe/Pt heterostructures with optimized layer thickness and magnetic field control.

Findings

THz emission is significantly enhanced by tuning Fe/Pt layer thickness.

Multilayer (Pt/Fe/MgO)$_n$ structures produce strong THz fields (~1.6 kV/cm).

THz emission spectrum and intensity are tunable with magnetic field.

Abstract

In this work, we report our study on the THz emission in Fe/Pt magnetic heterostructures. We have carried out a comprehensive investigation of THz emission from Fe/Pt magnetic heterostructures, employing time-domain THz spectroscopy. We reveal that by properly tuning the thickness of Fe or Pt layer, THz emission can be greatly improved in this type of heterostructure. We further demonstrate that the THz field strength emitted from a newly designed multilayer (Pt/Fe/MgO)$_n$ with n=3 can reach a value of ~1.6 kV/cm, which is comparable to the values from the conventional GaAs antenna with a bias of 4 kV/cm, and the nonlinear crystals, e.g., 100 micrometer GaP and 2 mm ZnTe. For the first time, the intensity and spectrum of THz wave is demonstrated to be tunable by the magnetic field applied on the patterned magnetic Fe/Pt heterostructures. These findings thus promise novel approaches to fabricate powerful and tunable THz emitters based on magnetic heterostructure.