U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Cindi L. Dennis (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 25 of 42

Thermosensitivity Through Exchange Coupling in Ferrimagnetic/Antiferromagnetic Nano-Objects for Magnetic Based Thermometry

March 6, 2023
Author(s)
Frank Abel, Eduardo De Lima Correa, Adam Biacchi, Thinh Bui, Solomon I. Woods, Angela R. Hight Walker, Cindi L. Dennis
Temperature is a fundamental physical quantity important to the physical and biological sciences. Measurement of temperature within an optically inaccessible three-dimensional (3D) volume at microscale resolution is currently limited. Thermal magnetic

Magnetic Characterization of Electrodeposited Pt1-xNix Alloy Films: Influence of Deposition Potential and the Presence of Boric Acid

September 21, 2022
Author(s)
Eric Rus, Eduardo De Lima Correa, Evan Groopman, Todd Williamson, Hussein Hijazi, Leila Kasaei, Leonard Feldman, Cindi L. Dennis, Thomas P. Moffat
Pt1-xNix (x = 0.25 to 0.92) thin films were examined for possible application as temperature sensing magnetic reporters. The alloys were prepared by charge-limited potentiostatic electrodeposition from aqueous chloride-based solutions in the presence and

Advanced characterization of magnetization dynamics in iron oxide magnetic nanoparticle tracers

January 5, 2022
Author(s)
Thinh Bui, Adam Biacchi, Brianna Bosch Correa, Cindi L. Dennis, Weston L. Tew, Angela R. Hight Walker, Solomon I. Woods
Characterization of the magnetization dynamics of single-domain magnetic nanoparticles (MNPs) is important for magnetic particle imaging (MPI), magnetic resonance imaging (MRI), and emerging medical diagnostic/therapeutic technologies. Depending on

The Suppression of Orange-Peel Coupling in Magnetic Tunnel Junctions by Pre-Oxidation

October 12, 2021
Author(s)
William F. Egelhoff Jr., Robert McMichael, Cindi L. Dennis, Mark D. Stiles, Alexander J. Shapiro, Brian B. Maranville, Cedric J. Powell
We have have found that pre-oxidation of the bottom Co electrode in magnetic tunnel junctions (MTJs) very effectively suppresses orange-peel coupling. The result is a free layer that is much softer. Work by others has demonstrated that pre-oxidation is

Thin Film Edge Property Measurements by Edge Saturation

October 12, 2021
Author(s)
Brian B. Maranville, Robert McMichael, Cindi L. Dennis, C A. Ross, J Cheng
Two techniques are described for characterizing the magnetic properties of the edges in long, straight magnetic stripes, using vector magnetometry. The critical transverse field at which the edge magnetization saturates is determined by measuring

Design and Engineering Colloidal Magnetic Particles for Nanoscale Thermometry

September 2, 2020
Author(s)
Adam J. Biacchi, Thinh Q. Bui, Cindi L. Dennis, Solomon I. Woods, Angela R. Hight Walker
Thermometry based on magnetic nanoparticles (MNPs) is an emerging technology that allows for remote temperature measurements throughout a volume that are impossible to achieve using conventional probe-based or optical methods. This metrology is based on

Quasi-two-dimensional magnon identification in antiferromagnetic FePS3 via magneto-Raman spectroscopy

February 18, 2020
Author(s)
Amber D. McCreary, Jeffrey R. Simpson, Thuc T. Mai, Robert D. McMichael, Jason E. Douglas, Nicholas P. Butch, Cindi L. Dennis, Rolando Valdes Aguilar, Angela R. Hight Walker
Recently it was discovered that van der Waals-bonded magnets retain long range magnetic ordering even down to a monolayer thickness, opening many avenues in fundamental physics and potential applications of these fascinating materials. One example is FePS3

Nanoparticle Architecture Preserves Magnetic Properties during Coating to Enable Robust Multi-Modal Functionality

August 23, 2018
Author(s)
Lauren E. Woodard, Cindi L. Dennis, Julie Borchers, Anilchandra Attaluri, Esteban Velarde, Charlene Dawidczyk, Peter C. Searson, Martin G. Pomper, Robert Ivkov
Mixed metal/metal oxide nanoparticles offer potential as multifunctional platforms for disease diagnosis and therapy, or 'theranostics' [1-9]. We describe the synthesis and characterization of gold/silica/iron oxide core-shell nanoparticles, for which the

Fe 2 MnGe: A Hexagonal Heusler Analogue

August 20, 2018
Author(s)
S. Keshavarz, N. Naghibolashrafi, Michelle E. Jamer, K. Vinson, D. Mazumdar, Cindi L. Dennis, William D. Ratcliff, Julie Borchers, A. Gupta, P. LeClair
Fe 2MnGe is a potential half-metallic full-Heusler L2 1 ferromagnetic compound with large spin polarization (approximately equal}97%) useful for various spintronic applications according to our first principles calculations using density functional theory

Electric-field control of perpendicular magnetic anisotropy in multiferroic PZT- and PMN- PT//[Co/Ni] composites with negative magnetostriction

July 4, 2018
Author(s)
Daniel B. Gopman, Andrew P. Chen, Cindi L. Dennis, June W. Lau, Robert D. Shull, Gregory P. Carman, Peter Finkel, Margo Staruch, Andres Chavez
A longstanding goal of spintronics is to identify alternatives to current-generated Oersted- fields for magnetization control at the nanoscale. An emerging approach seeks to harness the voltage-induced strain in a proximal piezostrictive layer to modify

Enhanced ferromagnetic resonance linewidth of the free layer in perpendicular magnetic tunnel junctions

March 3, 2017
Author(s)
Daniel B. Gopman, Cindi L. Dennis, Robert D. McMichael, Xiaojie Hao, Zihui Wang, Xiaobin Wang, Huadong Gan, Yuchen Zhou, Jian Zhang, Yiming Huai
We report the frequency dependence of the ferromagnetic resonance linewidth of the free layer in magnetic tunnel junctions with all perpendicular-to-the-plane magnetized layers. While the magnetic-fi eld-swept linewidth nominally shows a linear growth with

Magnetic Properties and Applications of Engineered Nanomaterials

January 20, 2017
Author(s)
Cindi L. Dennis
This chapter will review the fundamentals of nanomagnetism, including its origins, the different types, and their response at the nanoscale, followed by applications of nanomagnetics. Unfortunately, due to space constraints, this chapter cannot be

Artifacts in magnetic measurements of fluid samples

August 24, 2016
Author(s)
Cindi L. Dennis, Zoe A. Boekelheide
Applications of magnetic fluids are ever increasing, as well as the corresponding need to be able to characterize these fluids in situ. Commercial magnetometers are accurate and well-characterized for solid and powder samples, but their use with fluid

Effect of Grain Constraint on the Field Requirements for Magnetocaloric Effect in Ni(sub45)Co(Sub5)Mn(Sub40)Sn(sub10) Melt-Spun Ribbons

August 21, 2016
Author(s)
N. M. Bruno, Y. J. Huang, Cindi L. Dennis, J. G. Li, Robert D. Shull, J. H. Ross Jr., Y. I. Chumlyakov, I. Karaman
The influence of grain constraint on the magnetic field levels required to complete the isothermal martensitic transformation in magnetic shape memory alloys has been demonstrated for a NiCoMnSn alloy and the magnetocaloric performance of an optimally heat

Measurement and Modeling of Polarized Specular Neutron Reflectivity in Large Magnetic Fields

August 1, 2016
Author(s)
Brian B. Maranville, Brian J Kirby, Alexander J Grutter, Paul Kienzle, Charles F. Majkrzak, Yaohua Liu, Cindi L. Dennis
The presence of a large applied magnetic field removes the degeneracy of the vacuum energy states for spin-up and spin-down neutrons. For polarized neutron reflectometry, this must be included in the reference potential energy of the Schrodinger equation

Magnetocaloric Response Of Non-Stoichiometric Ni(sub2)MnGa Alloys and the Influence of Texture

November 1, 2015
Author(s)
Michael V. McLeod, Anit Giri, Brigitte A. Paterson, Cindi L. Dennis, H L. Zhou, S C. Vogel, Yong Ho Sohn, Robert D. Shull, B S. Majumdar
Currently, there is significant interest in magnetocaloric materials for solid state refrigeration. In this work, polycrystalline Heusler alloys belonging to the Ni(sub2+x)Mn(sub 1-x) Ga family, with x between 0.08 and 0.24, were evaluated for the purpose

Internal Magnetic Structure of Nanoparticles Dominates Time-Dependent Relaxation Processes in a Magnetic Field

June 2, 2015
Author(s)
Cindi L. Dennis, Kathryn L. Krycka, Julie Borchers, Ryan D. Desautels, Johan van Lierop, Natalie F. Huls, Andrew J. Jackson, Cordula Gruettner, Robert Ivkov
Time-dependent relaxation of nanomagnets, such as magnetic nanoparticles, have applications in many disciplines of science and technology because these magnets can exhibit hysteresis and loss power when exposed to AC magnetic fields. In particular, the

Details of the Magnetization Reversal in Patterned Exchange-biased and Unbiased Thin Films

November 1, 2014
Author(s)
Robert D. Shull, Y. P. Kabanov, Andrew P. Chen, Cindi L. Dennis, V S. Gornakov, Valerian I. Nikitenko
New features of the magnetization reversal of a patterned bilayer in the form of a square mesh consisting of 16 um wide intersecting stripes of Ni(sub79)Fe(sub21) (30 nm) exchange-coupled with IrMn (10 um) on top were revealed via use of the advanced

Solution-phase and Magnetic Approach Towards Understanding Iron Gall Inks

August 13, 2012
Author(s)
Harshita Kumari, Steven R. Kline, Cindi L. Dennis, Andrew V. Mossine, Rick L. Paul, Carol A. Deakyne, Jerry L. Atwood
Crystallization of compounds of iron with polyphenols, such as iron gall inks, has been an ongoing challenge. As with iron-gall inks, iron complexes of 1,2,3-trihydroxphenol-containing marocycles have also proved difficult to crystallize. Despite this