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Search Publications by: Virgil Provenzano (Assoc)

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Displaying 26 - 48 of 48

Subsolidus Phase Equilibria and Properties in the Magnetic Dielectric System Bi 2 O 3 :Mn 2 O 3+x :Nb 2 O 5

July 20, 2006
Author(s)
Terrell A. Vanderah, M W. Lufaso, A U. Adler, Igor Levin, Juan C. Nino, Virgil Provenzano, Peter K. Schenck, Robert S. Roth
Subsolidus phase relations have been determined for the Bi-Mn-Nb-O system in air (750-900 C). Phases containing Mn2+, Mn3+, and Mn4+ were all observed. Ternary compound formation was limited to pyrochlore, which formed a substantial solid solution region

Phase Formation, Crystal Chemistry, and Properties in the Magnetic Dielectric System Bi 2 O 3- Fe 2 O 3- Nb 2 O 5

June 22, 2006
Author(s)
M W. Lufaso, Terrell A. Vanderah, I M. Pazos, Igor Levin, Juan C. Nino, Virgil Provenzano, Peter K. Schenck, Robert S. Roth
Subsolidus phase relations have been determined for the Bi2O3-Fe2O3-Nb2O5 system in air (900-1075 C). Three new ternary phases were observed Bi3Fe0.5Nb1.5O9 with an Aurivillius-type structure, and two phases with approximate stoichiometries Bi17Fe2Nb31O106

The Effects of Small Metal Additions (Co, Cu, Ga, Mn, Al, Bi, Sn) on the Magnetocaloric Properties of the Gd 5 Ge 2 Si 2 Alloy

April 26, 2006
Author(s)
Robert D. Shull, Virgil Provenzano, Alexander J. Shapiro, A Fu, M W. Lufaso, E Karapetrova, G Kletetschka, V Mikula
It was shown that adding one atomic percent Fe to Gd5Ge2Si2 greatly reduced its large hysteresis losses, broadened the magnetic entropy change, ?Sm, versus temperature, T, peak, and shifted the ?Sm peak value from 275 K to 305 K[1]. The present paper

Structure and Magnetocaloric Properties of the Fe-Doped HoTiGe Alloy

April 20, 2006
Author(s)
Virgil Provenzano, B Baumgold, Robert D. Shull, Alexander J. Shapiro, Keiichi Koyama, Kazuo Watanabe, N K. Singh, K G. Suresh, A K. Nigam, S K. Malik
The structure and magnetocaloric properties of the Fe-doped HoTiGe compound were investigated by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD), superconducting quantum interference device (SQUID)

High Field X-Ray Diffraction Studies on Gd 5 (Ge 2-x Fe x )Si 2 (x = 0.05 and 0.2)

September 15, 2005
Author(s)
Jim L. Her, Keiichi Koyama, Kazuo Watanabe, Virgil Provenzano, F Fu, Robert D. Shull
We performed the X-ray diffraction measurements in magnetic fields up to 5 T for Gd5(Ge1.95Fe0.05)Si2 and Gd5(Ge1.8Fe0.2)Si2 which are noted recently as related materials for magnetic refrigerants. With heating from 8 K, the matrix of Gd5(Ge1.95Fe0.05)Si2

Peak Magnetocaloric Effects in Al-Gd-Fe Alloys

June 1, 2004
Author(s)
Virgil Provenzano, Alexander J. Shapiro, T T. King, E R. Canavan, P Shirron, M J. DiPirro, Robert D. Shull
The magnetocaloric properties of several AlxGdyFez (with x+y+z=100) ternary alloys have been determined between 2-300 K. Three distinct peaks in the magnetic entropy change Sm vs T were found: a low temperature peak (near 10 K), an intermediate temperature