The Effects of Small Metal Additions (Co,Cu,Ga,Mn,Al,Bi,Sn) on the Magnetocaloric Properties of the Gd5Ge2Si2 Alloy

R D Shull; V Provenzano; A J Shapiro; A Fu; Michael W. Lufaso; J Karapetrova; G Kletetschka; V Mikula

The Effects of Small Metal Additions (Co,Cu,Ga,Mn,Al,Bi,Sn) on the Magnetocaloric Properties of the Gd5Ge2Si2 Alloy

R D Shull, V Provenzano, A J Shapiro, A Fu, Michael W. Lufaso, J Karapetrova, G Kletetschka, V Mikula

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Abstract

The structural and magnetic properties of arc-melted and homogenized (1300 °C, 1&emsp13;h) alloys of Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Cu, Co, Ga, Mn, Al, Bi, or Sn) were investigated by powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and magnetometry. The addition of Cu, Ga, Mn, and Al completely eliminated the large hysteresis losses present in the undoped Gd 5 Ge 2 Si 2 alloy between 270 and 330&emsp13;K, broadened the magnetic entropy change Δ S m peak, and shifted its peak value from 275 to 305&emsp13;K similar to that observed earlier for Gd 5 Ge 1.9 Si 2 Fe 0.1 . The addition of Bi or Sn had a negligible effect on either the alloy hysteresis losses or the characteristics of the Δ S m vs T peak. The microstructure of the alloy doped with Cu, Co, Ga, Mn, or Al consisted of a majority phase (depleted of silicon) and a minor intergranular phase (rich in silicon and of the corresponding metal additive). For Bi or Sn doping, the microstructure consisted of only the Gd 5 Ge 2 Si 2 phase. Low temperature x-ray diffraction data on an Fe-doped sample showed the same spectra at 245 and 300&emsp13;K, consistent with the majority phase possessing an orthorhombic structure. Refrigeration capacity calculations show that Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Fe,Cu,Co,Ga,Mn,&emsp13;or&emsp13;Al) alloys are superior magnetic refrigerants compared to the undoped Gd 5 Ge 2 Si 2 alloy.

Original language	American English
Journal	Journal of Applied Physics
Volume	99
State	Published - Jan 2006

Keywords

germanium alloys; silicon alloys; copper alloys; cobalt alloys; gallium alloys; manganese alloys; aluminium alloys; bismuth alloys; tin alloys; alloying additions; magnetocaloric effects; X-ray diffraction; scanning electron microscopy
magnetic hysteresis
gadolinium alloys

Disciplines

Chemistry

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title = "The Effects of Small Metal Additions (Co,Cu,Ga,Mn,Al,Bi,Sn) on the Magnetocaloric Properties of the Gd5Ge2Si2 Alloy",

abstract = " The structural and magnetic properties of arc-melted and homogenized (1300 °C, 1&emsp13;h) alloys of Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Cu, Co, Ga, Mn, Al, Bi, or Sn) were investigated by powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and magnetometry. The addition of Cu, Ga, Mn, and Al completely eliminated the large hysteresis losses present in the undoped Gd 5 Ge 2 Si 2 alloy between 270 and 330&emsp13;K, broadened the magnetic entropy change Δ S m peak, and shifted its peak value from 275 to 305&emsp13;K similar to that observed earlier for Gd 5 Ge 1.9 Si 2 Fe 0.1 . The addition of Bi or Sn had a negligible effect on either the alloy hysteresis losses or the characteristics of the Δ S m vs T peak. The microstructure of the alloy doped with Cu, Co, Ga, Mn, or Al consisted of a majority phase (depleted of silicon) and a minor intergranular phase (rich in silicon and of the corresponding metal additive). For Bi or Sn doping, the microstructure consisted of only the Gd 5 Ge 2 Si 2 phase. Low temperature x-ray diffraction data on an Fe-doped sample showed the same spectra at 245 and 300&emsp13;K, consistent with the majority phase possessing an orthorhombic structure. Refrigeration capacity calculations show that Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Fe,Cu,Co,Ga,Mn,&emsp13;or&emsp13;Al) alloys are superior magnetic refrigerants compared to the undoped Gd 5 Ge 2 Si 2 alloy.",

keywords = "germanium alloys; silicon alloys; copper alloys; cobalt alloys; gallium alloys; manganese alloys; aluminium alloys; bismuth alloys; tin alloys; alloying additions; magnetocaloric effects; X-ray diffraction; scanning electron microscopy, magnetic hysteresis, gadolinium alloys",

author = "Shull, {R D} and V Provenzano and Shapiro, {A J} and A Fu and Lufaso, {Michael W.} and J Karapetrova and G Kletetschka and V Mikula",

year = "2006",

month = jan,

language = "American English",

volume = "99",

journal = "Journal of Applied Physics",

issn = "0021-8979",

}

TY - JOUR

T1 - The Effects of Small Metal Additions (Co,Cu,Ga,Mn,Al,Bi,Sn) on the Magnetocaloric Properties of the Gd5Ge2Si2 Alloy

AU - Shull, R D

AU - Provenzano, V

AU - Shapiro, A J

AU - Fu, A

AU - Lufaso, Michael W.

AU - Karapetrova, J

AU - Kletetschka, G

AU - Mikula, V

PY - 2006/1

Y1 - 2006/1

N2 - The structural and magnetic properties of arc-melted and homogenized (1300 °C, 1&emsp13;h) alloys of Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Cu, Co, Ga, Mn, Al, Bi, or Sn) were investigated by powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and magnetometry. The addition of Cu, Ga, Mn, and Al completely eliminated the large hysteresis losses present in the undoped Gd 5 Ge 2 Si 2 alloy between 270 and 330&emsp13;K, broadened the magnetic entropy change Δ S m peak, and shifted its peak value from 275 to 305&emsp13;K similar to that observed earlier for Gd 5 Ge 1.9 Si 2 Fe 0.1 . The addition of Bi or Sn had a negligible effect on either the alloy hysteresis losses or the characteristics of the Δ S m vs T peak. The microstructure of the alloy doped with Cu, Co, Ga, Mn, or Al consisted of a majority phase (depleted of silicon) and a minor intergranular phase (rich in silicon and of the corresponding metal additive). For Bi or Sn doping, the microstructure consisted of only the Gd 5 Ge 2 Si 2 phase. Low temperature x-ray diffraction data on an Fe-doped sample showed the same spectra at 245 and 300&emsp13;K, consistent with the majority phase possessing an orthorhombic structure. Refrigeration capacity calculations show that Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Fe,Cu,Co,Ga,Mn,&emsp13;or&emsp13;Al) alloys are superior magnetic refrigerants compared to the undoped Gd 5 Ge 2 Si 2 alloy.

AB - The structural and magnetic properties of arc-melted and homogenized (1300 °C, 1&emsp13;h) alloys of Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Cu, Co, Ga, Mn, Al, Bi, or Sn) were investigated by powder x-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy, and magnetometry. The addition of Cu, Ga, Mn, and Al completely eliminated the large hysteresis losses present in the undoped Gd 5 Ge 2 Si 2 alloy between 270 and 330&emsp13;K, broadened the magnetic entropy change Δ S m peak, and shifted its peak value from 275 to 305&emsp13;K similar to that observed earlier for Gd 5 Ge 1.9 Si 2 Fe 0.1 . The addition of Bi or Sn had a negligible effect on either the alloy hysteresis losses or the characteristics of the Δ S m vs T peak. The microstructure of the alloy doped with Cu, Co, Ga, Mn, or Al consisted of a majority phase (depleted of silicon) and a minor intergranular phase (rich in silicon and of the corresponding metal additive). For Bi or Sn doping, the microstructure consisted of only the Gd 5 Ge 2 Si 2 phase. Low temperature x-ray diffraction data on an Fe-doped sample showed the same spectra at 245 and 300&emsp13;K, consistent with the majority phase possessing an orthorhombic structure. Refrigeration capacity calculations show that Gd 5 Ge 1.9 Si 2 X 0.1 ( X = Fe,Cu,Co,Ga,Mn,&emsp13;or&emsp13;Al) alloys are superior magnetic refrigerants compared to the undoped Gd 5 Ge 2 Si 2 alloy.

KW - germanium alloys; silicon alloys; copper alloys; cobalt alloys; gallium alloys; manganese alloys; aluminium alloys; bismuth alloys; tin alloys; alloying additions; magnetocaloric effects; X-ray diffraction; scanning electron microscopy

KW - magnetic hysteresis

KW - gadolinium alloys

UR - https://digitalcommons.unf.edu/achm_facpub/9

M3 - Article

SN - 0021-8979

VL - 99

JO - Journal of Applied Physics

JF - Journal of Applied Physics

ER -

The Effects of Small Metal Additions (Co,Cu,Ga,Mn,Al,Bi,Sn) on the Magnetocaloric Properties of the Gd5Ge2Si2 Alloy

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