TY - JOUR
T1 - Hydrostatic compression effects on fifth-group element superconductors V, Nb, and Ta subjected to high-pressure torsion
AU - Mito, Masaki
AU - Shigeoka, Shun
AU - Kondo, Hirotaka
AU - Noumi, Nozomi
AU - Kitamura, Yuichiro
AU - Irie, Kunihiko
AU - Nakamura, Kazuma
AU - Takagi, Seishi
AU - Deguchi, Hiroyuki
AU - Tajiri, Takayuki
AU - Ishizuka, Mamoru
AU - Nishizaki, Terukazu
AU - Edalati, Kaveh
AU - Horita, Zenji
N1 - Funding Information:
This work was supported by JSPS KAKENHI Grant Number 17H03379 and 16K05460. This work was also supported by MEXT KAKENHI, a Grant-in-Aid for Scientific Research (S) (No. 26220909). The HPT process was carried out at the International Research Center on Giant Straining for Advanced Materials (IRC-GSAM) in Kyushu University.
Publisher Copyright:
© 2019 The Japan Institute of Metals and Materials
PY - 2019
Y1 - 2019
N2 - In fifth-group element superconductors V, Nb, and Ta, the increase in superconducting transition temperature (Tc) was attempted by using both high-pressure torsion (HPT) and additional hydrostatic pressure (HP) compression. The former brings about the grain refinement and strain accumulation in the unit-cell level. The additional compression for severely strained superconductors triggers strengthening intergrain-contact and/or structural deformation in the unit-cell level. The manner of the appearance of the above two effects depends on the kind of elements: First, in V, there is no prominent effect of HPT, comparing to the hydrostatic compression effects on its non-strained material. Next, in Ta, the effect of strengthening intergrain-contact appears at small hydrostatic compression, resulting in temporal increase in Tc. Finally, Nb exhibits prominent increase in Tc by both effects and, in particular, the structural deformation in the unit-cell level promotes the increase in Tc. Thus, the accumulation of residual strain in the level of starting material can be a promising work to manipulate Tc under HP compression.
AB - In fifth-group element superconductors V, Nb, and Ta, the increase in superconducting transition temperature (Tc) was attempted by using both high-pressure torsion (HPT) and additional hydrostatic pressure (HP) compression. The former brings about the grain refinement and strain accumulation in the unit-cell level. The additional compression for severely strained superconductors triggers strengthening intergrain-contact and/or structural deformation in the unit-cell level. The manner of the appearance of the above two effects depends on the kind of elements: First, in V, there is no prominent effect of HPT, comparing to the hydrostatic compression effects on its non-strained material. Next, in Ta, the effect of strengthening intergrain-contact appears at small hydrostatic compression, resulting in temporal increase in Tc. Finally, Nb exhibits prominent increase in Tc by both effects and, in particular, the structural deformation in the unit-cell level promotes the increase in Tc. Thus, the accumulation of residual strain in the level of starting material can be a promising work to manipulate Tc under HP compression.
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U2 - 10.2320/matertrans.MF201932
DO - 10.2320/matertrans.MF201932
M3 - Review article
AN - SCOPUS:85069736284
SN - 1345-9678
VL - 60
SP - 1472
EP - 1483
JO - Materials Transactions
JF - Materials Transactions
IS - 8
ER -