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Search Publications by: Joshua M. Pomeroy (Fed)

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Displaying 26 - 50 of 70

Charge state dependent energy deposition by ion impacts

August 5, 2011
Author(s)
Russell E. Lake, Joshua M. Pomeroy, Holger Grube, C E. Sosolik
We report on a measurement of craters in thin dielectric films formed by XeQ+ (26 Q 44) projectiles. Tunnel junction devices with ion-irradiated barriers were used to amplify the effect of charge-dependent cratering through the exponential dependence of

Magnetic Tunnel Junctions Fabricated Using Ion Neutralization Energy as a Tool

July 25, 2011
Author(s)
Joshua M. Pomeroy, Holger Grube, Pei-Ling Sun, Yun-Che Wang, Russell E. Lake
The neutralization energy of highly charged ions (HCIs) is used as an intermediate processing step to modify the electrical properties of magnetic tunnel junctions (MTJs), providing an additional degree of freedom in the devices’ fabrication. While most

HIGHLY CHARGED ION INTERACTIONS WITH THIN INSULATING FILMS

June 1, 2011
Author(s)
Joshua M. Pomeroy, Russell E. Lake, C E. Sosolik
The electrical conductance of magnetic tunnel junction (MTJ) devices whose ultra-thin aluminum oxide tunnel barrier was irradiated by highly charged ions (HCIs) increases linearly with the fluence of HCIs, while retaining a current-voltage relationship

Fe xvii X-ray Line Ratios for Accurate Astrophysical Plasma Diagnostics

February 20, 2011
Author(s)
John D. Gillaspy, E. H. Silver, L. Tedesco, Joseph N. Tan, Joshua M. Pomeroy, J M. Laming, G.-X. Chen, T. Lin
New laboratory measurements of the Ne-like Fe xvii x-ray lines in the 15-17 Angstrom range are presented, along with new theoretical predictions. These results establish consistency between independent laboratories and opens the door to trustworthy

EUV Spectral Lines of Highly-Charged Hf, Ta and Au Ions Observed with an Electron Beam Ion Trap

January 12, 2011
Author(s)
Ilija Draganic, Yuri Ralchenko, Joseph Reader, John D. Gillaspy, Joseph N. Tan, Joshua M. Pomeroy, Samuel M. Brewer, Dmitry D. Osin
Extreme ultraviolet spectra of highly charged hafnium, tantalum, and gold were produced with an electron beam ion trap (EBIT) at the National Institute of Standards and Technology (NIST) and recorded with a flat-field grazing-incidence spectrometer in the

Energy dissipation of highly charged ions on Al oxide films

March 3, 2010
Author(s)
Joshua M. Pomeroy, Russell Lake, C E. Sosolik
Slow highly charged ions carry a large amount of potential energy that can be dissipated within femtoseconds upon interaction with a surface. HCI-insulator collisions result in high sputter yields and surface nano-feature creation due to strong coupling

Measurement of the D Line Doublet in High-Z Highly-Charged Sodium-like Ions

July 8, 2009
Author(s)
John D. Gillaspy, Ilija Draganic, Yuri Ralchenko, Joseph Reader, Joseph N. Tan, Joshua M. Pomeroy, Samuel M. Brewer
We report a direct observation of the D line doublet of sodium-like ions with Z≥72. Spectra in the 1 nm to 9 nm spectral range are presented showing the widely split doublet for Hf61+, Ta62+, W63+,and Au68+. The ions were produced and confined in an

HCI Reduced Barriers in Magnetic Tunnel Junctions

December 7, 2008
Author(s)
Joshua M. Pomeroy, Holger Grube
In this paper, the use of tunnel junctions as sensors for determining the interaction strength between highly charged ions (HCIs) and ultra-thin insulating films is experimentally explored. HCIs are known to strongly ablate insulating materials upon

Highly charged ion (HCI) modified tunnel junctions

August 15, 2008
Author(s)
Joshua M. Pomeroy, Holger Grube
The neutralization energy carried by highly charged ions (HCIs) provides a fundamentally independent method for localizing energy on a target’s surface, producing features and modifying surfaces with fluences and kinetic energies that are negligible for

Spectra of W 39+ -W 47+ in the 12 nm to 20 nm Region Observed With an EBIT Light Source

October 14, 2007
Author(s)
Yuri Ralchenko, Joseph Reader, Joshua M. Pomeroy, Joseph N. Tan, John D. Gillaspy
We observed spectra of highly ionized tungsten in the extreme ultraviolet with an electron beam ion trap (EBIT) and a grazing incidence spectrometer at the National Institute of Standards and Technology. Stages of ionization were distinguished by varying

The Potential of Highly Charged Ions: Possible Future Applications

September 1, 2007
Author(s)
John D. Gillaspy, Joshua M. Pomeroy, A C. Perrella, Holger Grube
This paper mirrors and provides references to an invited review talk delivered by the first author at the 13th International Conference on the Physics of Highly Charged Ions. It briefly updates and extends an earlier review given in 2001 [1].

Selectable Resistance-Area Product by Dilute Highly Charged Ion Irradiation

August 13, 2007
Author(s)
Joshua M. Pomeroy, Holger Grube, A C. Perrella, John D. Gillaspy
In order to provide high performance read heads for future hard drive densities, considerable effort worldwide has been invested in developing techniques for producing low resistance area product (RA) magnetic tunnel junction sensors. In this letter, we

Gold Nanostructures Created by Highly Charged Ions

June 28, 2007
Author(s)
Joshua M. Pomeroy, Holger Grube, A C. Perrella, John D. Gillaspy
Nanometer sized structures produced by individual highly charged ion (HCI)impacts are reported for the first time on a high conductivity surface andexamined by scanning tunnelling microscopy (STM). Highly charged ions, e.g.,Bi$^{81+}$, represent an exotic

EUV Spectroscopy of Highly Charged Xenon Ions Created Using an Electron Beam Ion Trap

March 27, 2007
Author(s)
K Fahy, E Sokell, G O'Sullivan, A Aguilar, Joshua M. Pomeroy, Joseph N. Tan, John D. Gillaspy
At the NIST Electron Beam Ion Trap (EBIT), extreme-ultraviolet spectra of xenon ions have been recorded using a flat-field spectrometer. The electron beam energy was varied from 180 eV to 8 keV and radiation from charge states Xe6+ to Xe43+ was observed