Department of
Materials Science and Engineering
2005 Spring Seminar Series
April 15
11:00 - 12:00, 302 Collegiate Square
Single Atom Spintronics
Dr. Harsh
D. Chopra
Thin Films and Nanosynthesis Laboratory
Materials Program
Mechanical and Aerospace Engineering Department
SUNY-Buffalo
Buffalo, NY
Abstract
Single atom spintronics (SASS) represents
the ultimate physical limit in device miniaturization.
SASS is characterized by ballistic electron transport,
and is a fertile ground for exploring new phenomena. In
addition to the ‘stationary’ (field independent)
scattering centers that have a small and fixed contribution
to total transmission probability of electron waves, domain
walls constitute an additional and enhanced source of
scattering in these magnetic quantum point contacts (QPCs),
the latter being both field and spin-dependent. Through
the measurement of complete hysteresis loops as a function
of quantized conductance, we present definitive evidence
of enhanced backscattering of electron waves by atomically
sharp domain walls in single-atom QPCs formed between
microfabricated thin films. The observed spin-valve like
behavior is realized by control over wall width and shape
anisotropy. This behavior also unmistakably sets itself
apart from any mechanical artifacts; additionally, measurements
made on single atom contacts provide an artifact-free
environment.
Biographical
Information
Harsh Deep Chopra (pronounced as ‘Hersh’) is Associate
Professor in Mechanical & Aerospace Engineering Department
at SUNY-Buffalo, which hosts the Materials Program at Buffalo.
Chopra graduated from the University of Maryland’ Materials
Department in December 1993. After his postdoctoral experience,
he joined SUNY-Buffalo in January 1998. Chopra’s primary
research interests are focused on magnetic functional material
(magnetic shape memory alloys, magnetostrictive materials)
in thin films, multilayers, and bulk form; and spintronics:
single-atom spintronics, GMR, and various forms of exchange
couplings.
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