Citation: Dlamini, Z.W.;
Vallabhapurapu, S.; Vallabhapurapu,
V.S. Resistive Switching Property of
Raw Organic Cow Milk for Memory
Application. Sustainability 2023, 15,
8250. https://doi.org/10.3390/
su15108250
Academic Editors: Athanasios
Ragkos and Alexandros Theodoridis
Received: 6 March 2023
Revised: 25 April 2023
Accepted: 27 April 2023
Published: 18 May 2023
Copyright: © 2023 by the authors.
Licensee MDPI, Basel, Switzerland.
This article is an open access article
distributed under the terms and
conditions of the Creative Commons
Attribution (CC BY) license (https://
creativecommons.org/licenses/by/
4.0/).
sustainability
Article
Resistive Switching Property of Raw Organic Cow Milk for
Memory Application
Zolile Wiseman Dlamini
1,2,
* , Sreedevi Vallabhapurapu
3
and Vijaya Srinivasu Vallabhapurapu
2
1
Department of Maths Science and Technology Education, Central University of Technology,
Bloemfontein 9300, South Africa
2
Deparment of Physics, University of South Africa, Roodepoort 1709, South Africa
3
School of Computing, University of South Africa, Roodepoort 1709, South Africa
* Correspondence: zoliledlamini@hotmail.com
Abstract: Organic material-based computer memory devices are critical for lowering the amount
of electronic waste. Toward this end, we here present the resistive switching property of metal-
insulator-metal type devices consisting of active layers made of raw organic cow milk. Our devices
were made up of fat-free, medium cream, and full cream raw cow milk active layers sandwiched
between indium-doped tin oxide and silver electrodes. These devices were created without the use
of heat or electricity, and because they use cow milk as their active layers, they do not pollute the
environment. The medium-fat milk film had a higher weight percentage of metallic ions than the
fat-free and full-cream milk films, according to energy-dispersive X-ray spectroscopy analysis of the
active layers. As a result, electrical characterization and memory studies revealed that conductive
filaments driven by a space-charge-limited conduction mechanism were responsible for the “S-type”
memory characteristics of the medium-fat milk-based device, with switching at remarkably low
V
SET
=+0.48 V and V
RESET
= -0.25 V. Furthermore, with over 30 write/erase cycles, this device
demonstrated better non-volatile computer memory device prospects. Hoping conduction-driven
conductive filaments, on the other hand, were linked to the behavior of devices that use fat-free and
full-cream milk. Overall, our findings show that the fat and ion content of milk plays an important
role in the morphology, transport, and switching of these devices.
Keywords: resistive switching; cow milk; organic ReRAM; conduction mechanism
1. Introduction
Low-power and environmentally friendly computing devices are critical for realizing
the green computing world. Hickmott’s discovery of the resistive switching phenomenon
in ternary oxides in 1962 paved the way for the investigation of novel computer memory
devices, commonly referred to as resistive switching memories (ReRAMs) [1]. The ReRAMs
exhibit a sandwich-type architecture with two terminals and two dimensions, specifically a
Metal-insulator-metal configuration. The active layer is positioned between two electrodes.
This particular device exhibits the ability to manifest two distinct conductive states that
are mutually interchangeable via electrical means. Despite the predominant emphasis
on inorganic materials in ReRAM research, a significant breakthrough was made in 2006
when resistive switching was observed in organic materials, specifically in Tobacco mosaic
virus [2]. The findings reported by Tseng and colleagues have resulted in a significant
shift in the resistive switching research paradigm, as they have unveiled a novel cate-
gory of resistive switching materials. Additionally, research studies have demonstrated
that resistive switching memories based on organic materials, commonly referred to as
organic ReRAMs, exhibit promising potential for low power consumption [3]. To operate
the ReRAM, the SET (or write) process involves applying an electric stimulus across the
electrodes to turn ‘ON’ the device by switching its resistance from a high resistive state
Sustainability 2023, 15, 8250. https://doi.org/10.3390/su15108250 https://www.mdpi.com/journal/sustainability