The Fall 2021 MatSE 590 for graduate students consists of an exciting and jam-packed schedule. MATSE 590 is a colloquium (1-3 credits) consist of a series of individual lectures by faculty, students, or outside speakers.
Graduate students will receive a weekly email with information via @psu.edu email. Graduate students are required to attend all 590 Seminars. If you have any questions, please email Hayley Barnes at hjc24@psu.edu.
*Due to the ongoing Covid Pandemic this program is being offered virtually through Zoom. Please reference the weekly email from Hayley Barnes (hjc24@psu.edu) for Zoom link.
Tuesday, November 16, 2021
"Emergent Magnetic Order in PdCoO2 Thin Films"
Matthew Brahlek, R&D staff scientist, Quantum Heterostructures group, Materials Science and Technology Division, Oak Ridge National Laboratory
Abstract
The strongly correlated transition metal oxides are key candidates for next-generation electronic applications. This is due to a wide variety of unexpected and often unpredictable phenomena, which arise due to non-trivial coupling of the electronic and magnetic degrees of freedom. Understanding this complexity has proven a key challenge to create and ultimately control functional properties in these systems. Towards this, the 2-dimensional layered ABO2 metallic delafossites exhibit disparate properties such as ultra-high conductivities stemming from the metallic in-plane bonding of the A-layers and highly localized states within the octahedrally-coordinated, ionically bonded BO2 layers. In this talk I will discuss synthesizing high-quality epitaxial thin films of the archetypal metallic delafossite PdCoO2 by molecular beam epitaxy. By controlling the local strain, the metastability of the highly localized, yet zero-spin Co3+ is shown to induce ferromagnetic order. Systematically tracking how this emergent magnetic order arises out of the Pauli paramagnetic ground state reveals an unusual interplay of the itinerate Pd states and the magnetic Co states. This fundamental work highlights novel phenomena in a new class of oxides and will open new applications through the design and control of magnetism at the atomic scale.
Biographical Information
Matthew Brahlek is an R&D Staff in the Quantum Heterostructures group in the Materials Science and Technology Division at Oak Ridge National Laboratory focusing on the growth of thin film quantum materials by molecular beam epitaxy (MBE) and quantum transport properties. Previously, he was a postdoctoral scholar in the Department of Materials Science and Engineering at Penn State University where he developed the hybrid metal-organic MBE (hMBE) growth technique for ABO3 perovskites. He received his PhD in Physics from Rutgers University in 2014 focusing on the MBE growth of the highest quality topological insulators. His broad research interests are on developing and perfecting the MBE growth of new complex material systems to drive discoveries, and, ultimately, the ability to engineer quantum phenomena. Award for Encouragement in 2015 and Warren and Gisela Kennedy Keystone Research Scholar in 2019.
| Attachment | Size |
|---|---|
 Matthew Brahlek | 1.81 MB |