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Pa c ific Science R e vi e w 16 !"1#$ # %e#&ww w .els e vie r .com'loca te'(scr
S)nt*eses of new rare+eart* r*odi,mborocarbides
Toets, S*is*idoa-- /,nio Y,b,ta
b- Ta0ao ori
c- S*i2er, O0ada
d- Ta0as*i Yamasa0i
d- A0ira Yos*i0awa
e
a345He- 4R- To*o0, niversit)- 7a(an
b4R- To*o0, niversit)- 7a(an
cA3A-3ational 4nstit,te for aterials Science- 7a(an
dDe(artment of Science and En2ineerin2- /o0,s*i0an niversit)- 7a(an
e4R- 345He- To*o0, niversit)- 7a(an
Available online 16 Se(tember !"1#
Abstract
Sin2le cr)stals of a new 8,aternar) com(o,nd- ErR*!B!5- were obtained b) t*e fl,9 2rowt* met*od ,sin2 molten co((er as a
fl,9. T*e e9tracted cr)stals s*ow 2olden+colo,red l,ster and a ma9im,m si:e of a((ro9imatel) 1 1 "."! mm;. T*is
com(o,nd *as tetra2onal s)mmetr) and a((eared to be a derivative of t*e T*5r!Si!+t)(e< t*e lattice (arameters are a =
".;6&!$ nm and c = 1."%%!";$ nm. T*e electrical resistivit) (arallel to t*e a+b (lane of t*e cr)stal decreases wit*decreasin2 tem(erat,re. T*e
resid,al resistance ratio r !>; /$'r1.% /$ is 1.;&. 3o s,(ercond,ctivit) was observed down to 1.% /. T*e searc* for similar
t)(es of new com(o,nds was (erformed ,sin2 t*e arc+meltin2 s)nt*etic met*od. T*e new 8,aternar) RR* !B!5 com(o,nds are
obtained for R = ?a e Er e9ce(t E,$ and Y. T*e (*ase stabilit) of RR*!B!5 was disc,ssed.5o()ri2*t @ !"1#- ar Eastern ederal niversit)- /an2nam niversit)- Dalian niversit) of Tec*nolo2)- /o0,s*i0anniversit).
Prod,ction and Hostin2 b) Elsevier B.. All ri2*ts reserved.
/e)wordsC ErR*!B!5< T*5r!Si!+t)(e com(o,nd< Sin2le cr)stal< l,9 2rowt*< Electric (ro(erties
4ntrod,ction
St,dies *ave accelerated on R++B+5 R = rare
eart* element- = transition element$- enco,ra2ed b)
5orres(ondin2 a,t*or.
E+mail addressesC s*is*ido im r .to*o0,.ac.( T. S*is*ido$-
),b , taim r .to*o0,.ac.( /. Y,b,ta$- OR4.T a0aon ims.2o.(
T. ori$- so0ada0o0 , s*i0an.ac.( S. O0ada$- )amasa0 i
0o0,s*i0an.ac.( T. Yamasa0i$- )os*i0a w aim r .to*o0.ac.( A.
Yos*i0awa$.
Peer review ,nder res(onsibilit) of ar Eastern ederal niver+
sit)- /an2nam niversit)- Dalian niversit) of
Tec*nolo2)- /o0,s*i0an niversit).
re(orts on borocarbides com(osed of fo,r elements
s,c* as Ye3ieBe5 and YePdeBe5< t*ese com+
(o,nds s*ow *i2* s,(ercond,ctin2 transition tem(er+
at,res F1-!G. Alt*o,2* it is reco2nised t*at t*ere areman) interestin2 com(o,nds amon2 s,c* 8,aternar)
s)stems in terms of t*e coe9istence of ma2netism and
s,(ercond,ctivit)- etc.- efforts to s)stematicall) searc*
for s,c* com(o,nds still seem to be ins,fficient.
T*is st,d) is an attem(t to s)nt*esise new bor+
ocarbides in t*e s)stem of EreR*eBe5 ,sin2 a
molten metal fl,9 2rowt* met*od and aims to s)nt*e+
sise com(o,nds directl) as sin2le cr)stals. As a res,lt-
t*e new com(o,nd ErR*!B!5 is obtained. T*e cr)stal
*tt(C''d9.do i.or2 '1".1"16'.(s c r .!"1#."&.""1!!+%#%"'5o()ri2*t @ !"1#- ar Eastern ederal niversit)- /an2nam niversit)- Dalian niversit) of Tec*nolo2)- /o0,s*i0an
niversit). Prod,ction and Hostin2 b) Elsevier B.. All ri2*ts reserved.
http://www.sciencedirect.com/science/journal/12295450http://dx.doi.org/10.1016/j.pscr.2014.08.009http://dx.doi.org/10.1016/j.pscr.2014.08.009http://dx.doi.org/10.1016/j.pscr.2014.08.009http://dx.doi.org/10.1016/j.pscr.2014.08.009http://www.elsevier.com/locate/pscrmailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]://dx.doi.org/10.1016/j.pscr.2014.08.009http://dx.doi.org/10.1016/j.pscr.2014.08.009http://dx.doi.org/10.1016/j.pscr.2014.08.009http://www.elsevier.com/locate/pscrmailto:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]:[email protected]://dx.doi.org/10.1016/j.pscr.2014.08.009http://www.sciencedirect.com/science/journal/12295450 -
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#6 T. S*is*ido et al. ' Pacific Science Review 16 !"1#$ #%e#&
i2. 1. T*e 2rowt* (roced,re of t*e sin2le cr)stals of 8,aternar)
borocarbide in t*e EreR*eBe5 s)stem b) t*e fl,9 met*od ,sin2
molten 5, as a fl,9.
str,ct,re and electronic (ro(erties of t*e new com+
(o,nd are anal)sed e9tensivel) ,sin2 t*e arc+meltin2
s)nt*etic met*od. T*e (*ase stabilit) of t*e new bor+ocarbides is determined.
E9(erimental details
T*e materials ,sed in t*e fl,9 2rowt* e9(eriment
were erbi,m bloc0- .I (,re$- r*odi,m (owder-
.6I$- boron a22lomerate- .&6I$ and carbon
bloc0- .I$. or one wei2*t (art of eac* sol,te-
1" wei2*t (arts of 5, bloc0- .I$ were ,sed as afl,9. T*e mi9t,re of t*e sol,te and fl,9 was (laced into
a *i2* (,rit) al,mina cr,cible. P,rified He 2as flowed
into t*e f,rnace at a rate of !"" m?'min and (rotected
t*e atmos(*ere a2ainst o9idation. T*e mi9t,re of t*e
raw materials and fl,9 was *eated to 16>; / at a rate
of #"" /'* and was *eld at t*at tem(erat,re for 1" *.
T*e sol,tion was cooled to 1;%; / at a rate of % /'*
and t*en f,rnace cooled. T*e e9tracted cr)stals were
se(arated b) dissolvin2 5, in dil,te nitric acid. i2. 1
s*ows t*e 2rowt* (roced,re of t*e sin2le cr)stals of
t*e 8,aternar) borocarbides in t*e Ere
R*e
Be
5 s)s+tem b) t*e fl,9 2rowt* met*od ,sin2 molten 5, as a
fl,9. i2. ! s*ows t*e sc*ematic arran2ement of t*e
2rowt* a((arat,s and vertical tem(erat,re distrib,tion
of t*e sol,tion. To searc* for new com(o,nds- arc+
meltin2 s)nt*eses were carried o,t. T*e startin2 ma+
terials for t*e arc+meltin2 s)nt*eses were lant*anide
metals bloc0- .I$- r*odi,m (owder- .I$-
cr)stalline boron (owder- .&6I$ and carbon (ow+
der- .I$. T*ese elements were mi9ed in an
atomic ratio of 1C 1C 1C 1- 1C !C !C 1 and 1C ;C ;C 1 and
were arc+melted ,nder a 1 atm ar2on atmos(*ere on a
water+cooled co((er *eart*. T*e solidified b,tton was
i2. !. T*e 2eometrical arran2ement of t*e 2rowt* f,rnace and vertical tem(erat,re distrib,tion of t*e sol,tion.
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T. S*is*ido et al. ' Pacific Science Review 16 !"1#$ #%e#& #>
i2. ;. SE (*oto2ra(* of a ErR*!B!5 cr)stal e9tracted from t*e
5, fl,9.
t,rned over and re+melted t*ree times to ens,re*omo2eneit).
T*e mor(*olo2ical (ro(erties of t*e cr)stals were
investi2ated b) electron microsco() SE$. T*e
c*emical com(osition of t*e sam(les was anal)sed
,sin2 ind,ctivel) co,(led (lasma atomic emission
s(ectrometr) 45P+AES$. 5r)stal str,ct,re determina+
tion was carried o,t ,sin2 an J+ra) (owder
i2. #. T*e cr)stal str,ct,re of ErR*!B!5.
i2. %. T*e tem(erat,re de(endence of electric resistivit) for t*e
ErR*!B!5 cr)stal.
diffractometer- a (recession camera- and a fo,r+circle
J+ra) diffractometer.
Res,lts and disc,ssion
rom t*e sol,te wit* t*e com(osition of ErC R*C BC
5 = 1C !C !C 1 and 5, fl,9- s*inin2 2olden s8,are+
(lated sin2le cr)stals were obtained i2. ;$.
T*e res,lts of t*e c*emical anal)sis for t*e (lat)cr)stals indicate t*at t*e c*emical form,la of t*e
com(o,nd is ErR*!B!5 F;e6G. Ot*er sin2le cr)stals
were co+e9tracted- mainl) *e9a2onal col,mnar ones-
w*ic* were determined to be ErR*;B!- a 0nown
com(o,nd. rom t*e ot*er startin2 com(ositions- ErC
Table 1
5r)stallo2ra(*ic data and electric (ro(erties of ErR*!B!5.
5r)stallo2ra(*ic dataC
5*emical form,la ErR*!B!5
5r)stal s)stem Tetra2onal
Str,ct,re t)(e Derivative of T*5r!Si! t)(e3,mber of molec,le
(er ,nit cell- K !
?attice (arameter
a nm$ ".;6& !$
c nm$ 1."%%!";$
nit cell vol,me-
1" !&
m;$ 1.#;!>
Electric (ro(ertiesC
Resistivit) at !>; / mcm$ ".1#>
Resistivit) at #.! / mcm$ ".1">
Resid,al resistivit) ratio RRR
r !>; /$'r1.% /$ 1.;&
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i2. 6. T*e lattice (arameters of t*e newl) obtained RR* B 5
RR*!B!5 (*ases was determined to be R = Er. ,rt*er
c*aracterisations of t*e newl) discovered com(o,nds
are in (ro2ress.
5oncl,sions
Sin2le cr)stals of a new 8,aternar) borocarbide-
ErR*!B!5- were s,ccessf,ll) obtained from a molten
co((er sol,tion. T*e) are s*in) 2olden s8,are (lates
,( to 1 1 "."! mm;$. Str,ct,ral anal)sis dem+
onstrates t*at t*e com(o,nd belon2s to a tetra2onal
s)stem based on t*e T*5r!Si!+t)(e wit* lattice con+
stants a = ".;6&!$ nm and c = 1."%%!";$ nm. An
investi2ation of t*e electrical resistance in t*e tetra2+
onal ""1$ (lane of t*e sin2le cr)stals revealed t*at t*e
cr)stals be*ave metallicall). B) coolin2 t*e cr)stals to
1.% /- no s,(ercond,ctin2 transition is observed. T*e
resid,al resistance ratio r !>; /$'r 1.% /$ is 1.;&.T*ese data are s,mmarised in Table 1. T*e ran2e of R-
w*ic* is (rod,ced b) t*e arc meltin2 s)nt*esis- was
R = ?a e Er- e9ce(t E,$.! !
investi2ated. 4t was determined t*at R = ?a Ere9ce(t E,$ and Y< t*e si:e limitation for t*e formation
R*C BC 5 = 1C 1C 1C 1 and 1C ;C ;C 1- t*e amo,nts of
(lat) sin2le cr)stals to t*e total (rod,cts obtained
were lower. T*e co+e9tracted (rod,cts were mainl)
*e9a2onal col,mnar ErR*;B! from 1C 1C 1C 1 and
irre2,larl) s*a(ed R*B from 1C ;C ;C 1. ErR*!B!5belon2s to t*e tetra2onal s)stem based on t*e
T*5r!Si! t)(e. i2. # s*ows t*e cr)stal str,ct,re of
ErR*!B!5. T*e lattice (arameters of ErR*!B!5 are
a = ".;6&!$ nm and c = 1."%%!";$ nm. Str,ct,ral
anal)sis- wit* t*e c*emical form,la ass,med to be
ErR*!B!5- )ielded stron2 reliabilit) factors
R = "."!6 and Rw = "."!1. Lit* fo,r (robes attac*ed
to t*e flat s,rface of t*e ""1$ (lane of t*e cr)stal-
c*an2es in t*e electrical resistance wit* tem(erat,re
were meas,red. T*e com(o,nd be*aves li0e a
metallic com(o,nd i2. %$. 3o s,(ercond,ctin2
transition is observed down to 1.% /. T*e val,e of t*e
resid,al resistance ratio r !>; /$'r 1.% /$ is 1.;&.
T*ese data are s,mmarised in Table 1.
A searc* for similar com(o,nds is (erformed
e9tensivel) ,sin2 t*e arc+meltin2 s)nt*etic met*od. As
a res,lt- we determined t*at ?a e Er e9ce(t E,$ and
Y co,ld form a RR*!B!5 com(le9 i2. 6$. T*e
im(,rit) (*ase RR*;B! increases wit* decreasin2
rare eart* si:e. 3amel)- t*e si:e limitation of t*e
formation of t*e
of RR*!B!5 (*ases was determined to be R = Er.
,rt*er c*aracterisations of t*e new com(o,nds are
now in (ro2ress F>-&G FG.
Ac0nowled2ements
T*e (resent a,t*ors wo,ld li0e to e9(ress t*eir
2ratit,de to Dr. 7. Ye of 34S for *er *el(f,l disc,s+
sions. T*e a,t*ors are also indebted to s. A. 3om,ra-
essrs. T. S,2awara- S. To:awa- /. Obara- Y. ,r+
a0ami and S. 4to of 4R at To*o0, niv. for t*eir
tec*nical contrib,tions. T*e c*emical anal)ses
com(leted b) t*e staff of AR5A and Dr. T. As*ino
of 4R at To*o0, niv. are 2ratef,ll) a((reciated.
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