Mic os uc u e and magne ism o Co2FeAl Heusle alloy p epa ed by a c and
induc ion mel ing compa ed wi h plana low cas ing
A. Ti o , Y. Ji asko a, O. Zi o sky, J. Bu sik, and D. Janicko ic
Ci a ion: AIP Ad ances 8, 047206 (2018); doi: 10.1063/1.4993698
View online: h ps://doi.o g/10.1063/1.4993698
View Table o Con en s: h p://aip.sci a ion.o g/ oc/ad /8/4
Published by he Ame ican Ins i u e o Physics
A icles you may be in e es ed in
Decomposing he pe meabili y spec a o nanoc ys alline ineme co e
AIP Ad ances 8, 047205 (2018); 10.1063/1.4991941
In es iga ion o measu emen me hod o sa u a ion magne iza ion o i on co e ma e ial using elec omagne
AIP Ad ances 8, 047202 (2018); 10.1063/1.4993998
Dependence o magne ic pe meabili y on esidual s esses in alloyed s eels
AIP Ad ances 8, 047201 (2018); 10.1063/1.4994202
C i ical exponen analysis o ligh ly ge manium-doped La0.7Ca0.3Mn1-xGexO3 (x = 0.05 and x = 0.07)
AIP Ad ances 8, 047204 (2018); 10.1063/1.4993412
Using magne ic cha ge o unde s and so -magne ic ma e ials
AIP Ad ances 8, 047301 (2018); 10.1063/1.4994219
Ve y low equency noise educ ion in o hogonal luxga e
AIP Ad ances 8, 047203 (2018); 10.1063/1.4994208
AIP ADVANCES 8, 047206 (2018)
Mic os uc u e and magne ism o Co2FeAl Heusle alloy
p epa ed by a c and induc ion mel ing compa ed
wi h plana low cas ing
A. Ti o ,1,2,aY. Ji asko a,2,3 O. Zi o sky,1J. Bu sik,3and D. Janicko ic4
1Depa men o Physics, VSB-Technical Uni e si y o Os a a, Os a a-Po uba 708 33,
Czech Republic
2CEITEC IPM, Ins i u e o Physics o Ma e ials, AS CR, B no 616 62, Czech Republic
3Ins i u e o Physics o Ma e ials, AS CR, B no 616 62, Czech Republic
4Ins i u e o Physics, Slo ak Academy o Sciences, B a isla a 845 11, Slo akia
(Recei ed 30 June 2017; accep ed 2 Oc obe 2017; published online 19 Oc obe 2017)
This pape is de o ed o in es iga ions o he s uc u al and magne ic p ope ies o
he Co2FeAl Heusle alloy p oduced by h ee echnologies. The alloys p epa ed by
a c and induc ion mel ing ha e esul ed in coa se-g ained samples in con as o he
ine-g ained ibbon- ype sample p epa ed by plana low cas ing. Scanning elec on
mic oscopy comple ed by ene gy dispe si e X- ay spec oscopy, X- ay di ac ion,
M¨
ossbaue spec oscopy, and magne ic me hods sensi i e o bo h bulk and su ace
we e applied. The chemical composi ion was sligh ly di e en om he nominal only
o he ibbon sample. F om he iewpoin o magne ic p ope ies, he bulk coe ci i y
and emnan magne iza ion ha e ollowed he s uc u e in luenced by he echnology
used. Sa u a ion magne iza ion was p ac ically he same o samples p epa ed by a c
and induc ion mel ing, whe eas he magne iza ion o ibbon is sligh ly lowe due o a
highe Al con en a he expense o i on and cobal . The su ace magne ic p ope ies
we e ma kedly in luenced by aniso opy, g ain size, and su ace oughness o he sam-
ples. The su ace oughness and b i leness o he ibbon- ype sample did no make
domain s uc u e obse a ion possible. The o he wo samples could be well polished
and hei highly smoo h su ace has enabled domain s uc u e isualiza ion by bo h
magne o-op ical Ke mic oscopy and magne ic o ce mic oscopy. © 2017 Au ho (s).
All a icle con en , excep whe e o he wise no ed, is licensed unde a C ea i e
Commons A ibu ion (CC BY) license (h p://c ea i ecommons.o g/licenses/by/4.0/).
h ps://doi.o g/10.1063/1.4993698
I. INTRODUCTION
The Heusle alloys s ill a ac ema kable a en ion ega ding a ious composi ions, physical
p ope ies, and subsequen applica ions.1This is documen ed by an inc easing numbe o scien i ic
pape s in ecen yea s, abou 500 in o al. The Heusle alloys a e cha ac e ized by he o mula X2YZ,
whe e X and Y a e ansi ion me als (e.g. Fe, Co, Mn) and Z is an elemen om a g oup III, IV, o V.
Basically, his o mula consis s o wo bina y B2 compounds XY and XZ bo h o CsCl ype c ys al
s uc u e. This means ha an abili y o a compound o o m he B2 s uc u e can also indica e he
possibili y o o m a Heusle alloy. Among a huge numbe o a ious composi ions, he Co-based
Heusle compounds a e o pa icula in e es because hey a e good e omagne ic ma e ials, show
compa a i ely high Cu ie empe a u es, up o 1000 K, and ha e ela i ely low deg ees o a omic
diso de ing.2Mo eo e , i was epo ed ha hei unnelling magne o esis ance can exceed up o
1000%.3,4This makes Heusle -based de ices a ac i e o magne ic da a s o age applica ions.
A p esen , Co2FeAl belongs o one o he mos s udied Heusle alloys. I p o ides huge unnelling
magne o esis ance a io in magne ic unnel junc ions5,6bu also a low Gilbe damping7essen ial o
aCo esponding au ho . Email: and ii. i o @ sb.cz
2158-3226/2018/8(4)/047206/10 8, 047206-1 ©Au ho (s) 2017
047206-2 Ti o e al. AIP Ad ances 8, 047206 (2018)
spin swi ching wi h low cu en s and spin o que oscilla o s. The use o Co2FeAl as a e omagne ic
ma e ial in spin onic de ices equi es deep knowledge and con ol o i s magne ic p ope ies. One
o he key pa ame e s is magne ic aniso opy, which is di ec ly ela ed o he spin-o bi -coupling
ela i is ic e ec . Magne ic aniso opy and i s changes can be e ec i ely modi ied by mic os uc u e
and he eby also by a modi ica ion o he elec onic s uc u e in bulk, su ace and/o in e aces.
The e a e se e al ways o syn hesize Heusle alloys. Beside con en ional echniques (e.g., a c
mel ing, comme cial induc ion u nace mel ing o s oichiome ic amoun s o he cons i uen s in a
p o ec i e noble gas a mosphe e in o a o m o bulk compounds,8mechanical alloying me hod,9,10
molecula beam epi axy,11 chemical ou e,12 elec ospinning me hod,13 co-p ecipi a ion ou e,14 e c.),
he e is ongoing e o o sea ch o non- adi ional p epa a ion echnologies which could p oduce
Heusle alloys wi h imp o ed p ope ies. This is also he case o he p esen s udy. The con en ional
a c and induc ion mel ing echnologies we e comple ed by he plana low cas ing echnology known
om he p epa a ion o amo phous and/o nanoc ys alline ma e ials in o a ibbon o m.
II. EXPERIMENTAL
A. Sample p epa a ion
Co2FeAl Heusle alloys we e p epa ed om high-pu i y elemen s: Fe – 99.95%, Co – 99.8%,
and Al – 99.95%. A c mel ing (AM) using a MAM-1 u nace (Buehle GmbH) and induc ion mel ing
(IM) we e used o he p oduc ion o bu on- and cylind ical- ype ingo s. Each a c-mel ed ingo was
mel ed ou imes o gua an ee a good homogenei y; he weigh loss was close o 1%. The ingo s
we e cu using spa k e osion in deionized wa e in o discs abou 500 µm hick. The su ace o he
disc-sample was i s g inded and polished o emo e oxides. Subsequen ly, he samples, deno ed
DAM and DIM, espec i ely, we e polished using Vib ome o 24 h o gua an ee he bes possible
su ace smoo hness. One cylind ical ype ingo was used o he p epa a ion o 2 mm wide and 20 µm
hick ibbons using plana low cas ing p ocedu e. This sample is deno ed by R. The high su ace
oughness o he ibbon and impossibili y o polishing owing o high b i leness we e he limi a ions
o he su ace sensi i e magne o-op ical and a omic o ce mic oscope obse a ion.
B. Expe imen al me hods
1. Scanning elec on mic oscopy (SEM)
A TESCAN LYRA 3XMU FEG/SEM scanning elec on mic oscope wo king a accele a ing
ol age o 20 kV equipped wi h an XMax80 Ox o d Ins umen s de ec o o ene gy dispe si e X- ay
analysis (EDX) was used o ollow he mo phology and mic os uc u e.
2. X- ay di ac ion (XRD)
An X’PERT PRO di ac ome e wi h Co Kα adia ion (λ= 0.17902 nm) was used o s udy he
s uc u al and composi ional p ope ies. The X- ay di ac og ams we e measu ed a oom empe a-
u e (RT) om 2θ= 35◦ o 135◦in s eps o 0.008◦and 500 s pe deg. The analysis o powde pa e ns
was ealized by HighSco e Plus p og am using he Rie eld s uc u e e inemen me hod15 and he
ICSD da abase o ino ganic and ela ed s uc u es.16 Besides he la ice pa ame e s o he analyzed
phases, he size o cohe en ly di ac ing domains and mic os ains we e ob ained om he pa e n
analysis.
3. M¨
ossbaue spec ome y (MS)
57Fe M¨
ossbaue spec ome y was used o gain insigh in o he s uc u al e olu ion o he local
en i onmen o he i on a oms. The measu emen s we e ca ied ou a RT using a 57Co(Rh) sou ce.
S anda d ansmission geome y was applied o he ibbon- ype R sample; backsca e ing geome y
using γ- ays o he disc- ype, DAM and DIM, samples. The calib a ion o eloci y scales in bo h
measu ing geome ies was pe o med wi h α-Fe and he isome shi s a e gi en wi h espec o he RT
M¨
ossbaue spec um o α-Fe. All spec a we e measu ed wi h nea ly he same quali y and e alua ed
wi hin he ansmission in eg al app oach using he CONFIT p og am.17 In he measu ed M¨
ossbaue
spec um, he c ys alline componen s a e ep esen ed by disc e e single-, double-, and/o six-line
047206-3 Ti o e al. AIP Ad ances 8, 047206 (2018)
Lo en zian sub-spec a de e mined by disc e e alues o hype ine pa ame e s: δ- isome shi (s),
∆- quad upole spli ing(s), and B- hype ine induc ion(s), co esponding o pa amagne ic (δand
∆) and/o e omagne ic (δ,∆, and B) phases, espec i ely. All componen s a e u he desc ibed by
hei in ensi ies, A.
4. Magne ic measu emen s
a. Bulk magne ic p ope ies. RT hys e esis loops we e ob ained using a ib a ing sample mag-
ne ome e (VSM) Mic osense EV9 wi h maximal magne ic ield up o 1600 kA/m. The magne ic
cha ac e is ics, coe ci i y, emnan and sa u a ion magne iza ions we e de i ed om he hys e esis
loops wi h he accu acy o ±1%. The magne ic measu emen s we e also applied o de e mine Henkel
plo s. Typically, hey a e cons uc ed using iso he mal emanence (IRM) and DC demagne iza ion
(DCD) cu es.18 Howe e , some simpli ica ions desc ibed in Re . 19 enable us o ob ain he same
in o ma ion using he ela ion be ween he ini ial ( i gin) cu e, MVIR(H), and magne iza ions a
inc easing MUP(H) and dec easing MDOWN(H) posi i e magne ic ields:
∆M(H)=MVIR(H)−(MUP(H) + MDOWN(H))/2. (1)
b. Su ace magne ic p ope ies. The su ace hys e esis loops o all samples (DAM, DIM, and R)
we e measu ed using he longi udinal and he pola magne o-op ical Ke e ec (MOKE), he ed lase
diode o 670 nm wa eleng hs and exp essed as he dependence o Ke o a ion on applied magne ic
ield. The con ibu ions o he in-plane longi udinal magne iza ion componen ML, pa allel o bo h
he applied magne ic ield and he plane o inciden ligh , and he ou -o -plane pola componen
MP, pe pendicula o he sample su ace, we e sepa a ed om he loops measu ed a an oblique
inciden angle o 50◦. These esul s we e con i med a no mal inciden geome y, when he pola
magne iza ion componen MPwas clea ly de ec ed. The su ace magne ic domain s uc u e was
obse ed by magne o-op ical Ke mic oscopy (MOKM) and by magne ic o ce mic oscopy (MFM)
wi h NTEGRA P ima pla o m ope a ed in semi-con ac mode.
III. RESULTS AND DISCUSSION
A. Mo phology, chemical and phase composi ion
The mo phology o as-p epa ed samples is shown in Fig. 1. The SEM mic og aphs o he DAM (a)
and DIM (b) samples clea ly documen hei coa se-g ained s uc u e. The g ain size a ies be ween
300 µm up o 500 µm, whe eas he g ains in he R sample a e subs an ially smalle , 1-3 µm. The
chemical analyses aken om he a ea o abou 1 mm2a he DAM and DIM samples and summa ized
in Table Ido no yield any impo an di e ence om he nominal composi ion. A de ailed analysis
o he indi idual g ains o he DAM sample has poin ed a dend i e s uc u e wi h a sligh ly highe
Al con en a he expense o Fe in dend i e co es (48.34 ±0.23 a .% Co, 22.20 ±0.46 a .% Fe, 29.46
±0.31 a .% Al). Une en d ople -like and lake-like shapes o R sample pieces did no enable us
s anda d su ace polishing; he EDX analyses in his case ha e la ge sca e as i is documen ed in
Table I, las ow.
The X- ay di ac og ams o DAM and DIM samples show i ually no di e ence and he e o e
only he di ac ion pa e n o he DAM sample is shown in Fig. 2a oge he wi h a sligh ly di e en
FIG. 1. Su ace mo phology o he a c mel ed, DAM, sample and de ail (inse ) o dend i e s uc u e obse ed a g ains
(a); o he induc ion mel ed, DIM, sample (b), and o he ibbon, R, sample (c).
047206-4 Ti o e al. AIP Ad ances 8, 047206 (2018)
TABLE I. Elemen concen a ions ob ained by EDX om a eas abou 1 mm2.
Sample Co (a .%) Fe (a .%) Al (a .%)
DAM 48.84 ±0.59 24.06 ±1.70 27.10 ±2.11
DIM 49.29 ±0.21 25.53 ±0.10 25.18 ±0.31
R 40.70 ±2.62 22.21 ±1.48 37.09 ±4.02
FIG. 2. XRD pa e ns o a c mel ed (DAM) sample (a) and ibbon (R) sample (b).
di ac ion pa e n o he R sample in Fig. 2b. The peaks a e labeled by co esponding h, k, l, alues.
In he ull-Heusle alloy o he chemical o mula X2YZ, he o de ed L21s uc u e (Fig. 3) and wo
kinds o diso de ed s uc u es e e ed o as B2 (Y-Z diso de ing) and A2 (X-YZ diso de ing) can
exis . Based on ela ions be ween a omic o de ings and supe la ice di ac ion lines, he pa e ns
can be di ided in o odd (h, k, l a e odd numbe s, e.g. (111)), e en ((h+k+l)/2 = 2n+1, e.g. (200)),
FIG. 3. Schema ic ep esen a ion o he L21s uc u e o ull-Heusle alloys; he X (Co) a oms a e placed on he Wycko
posi ion 8c, he Y(Fe) and Z(Al) a oms a e loca ed on 4a and 4b posi ions, espec i ely.

047206-5 Ti o e al. AIP Ad ances 8, 047206 (2018)
and undamen al (((h+k+l)/2 = 2n, independen o he o de ing s uc u es, e.g.(220)) di ac ion.20
The Rie eld analysis o measu ed da a o all samples was done using he ICSD 57 607 da abase21
o Co2FeAl alloy conside ing he L21s uc u e. I has yielded he la ice pa ame e 0.5733(4) nm
o he DAM and DIM samples and 0.5729(3) nm, o he R sample, i.e., i ually iden ical wi hin
an expe imen al e o . A sligh di e ence was ob ained only o he cohe en ly di ac ing domains
size, d(no equi alen o g ain size isible in Fig. 1), and la ice mic os ain, E. These pa ame e s
we e de e mined by compa ing he p o ile wid h o a s anda d p o ile wi h a sample p o ile acco d-
ing o he Sche e o mula (da e age =Kλ/((Bobs -Bs d)cosθ) and acco ding o he angen o mula
(E=√(B2obs -B2s d)/(4 anθ) using Size/S ain calcula o as a pa o p og ams X’Pe Da a iewe and
HighSco ePlus bo h by Panaly ical.15 The alues o DAM and DIM samples we e d= 50 ÷60 nm
and E= 0.210 % and o R sample d= 43 nm and E= 0.265 %. Ne e heless, i u ned ou ha his
ICSD 57 607 da abase is no oo sa is ac o y o analysis o p esen X- ay pa e ns. The de ec ed
ypes o supe la ice di ac ion lines (odd, e en, undamen al) ha e indica ed a complex a omic
o de ing. I s e alua ion, i.e., he deg ee o B2-o de ing and L21-o de ing has equi ed a mo e de ailed
analysis based on adi ional analy ical app oach o Webs e ,22 app op ia ely ex ended by Takamu a.23
This p oceeds a p esence and he esul s, exceeding he scope o his pape , will be published
elsewhe e.
FIG. 4. M¨
ossbaue spec a o he a c mel ed, DAM, (a), induc ion mel ed, DIM, (b), and plana low cas ing, R, (c) samples
esol ed in o e omagne ic (1, 2, 3, 4, see Table II) and pa amagne ic (see ex ) sub-componen s.
047206-6 Ti o e al. AIP Ad ances 8, 047206 (2018)
B. M¨
ossbaue spec ome y
Since M¨
ossbaue spec ome y is a highly sensi i e me hod o he s udy o magne ic p ope ies
on an a omic le el, i was also applied in he p esen in es iga ion. The main pu pose was o de ec
a om o de ing in he su oundings o esona ing Fe a oms and o see ine s uc u al di e ences
be ween he alloys p epa ed by a ious echnological condi ions. The Co2FeAl ull-Heusle alloy o
gene al o mula X2YZ c ys allizes in he L21s uc u e consis ing o ou cc subla ices shown in
Fig. 3.
The esona ing Fe a oms ha e Fe, Co, and Al a oms in hei neighbo hood; hei o de ing oge he
wi h s uc u e de ec s in luences he hype ine pa ame e s, namely hype ine induc ion and isome
shi . The quad upole spli ing in he ideal L21s uc u e should be, owing o cubic symme y, ze o.
The spec a o he DAM and DIM samples measu ed using γ- ays in he backsca e ing geome y
wi h a dep h sensi i i y o abou 30 µm a e shown in Figs. 4a and 4b and compa ed wi h he spec um
o he R sample, a he bo om in he same igu e, ob ained in ansmission geome y. All spec a
consis o he magne ically spli componen which was i ed using ou six-line sub-componen s
yielding he bes esul . The alues o he hype ine induc ion, isome shi and ela i e a ea o
indi idual sub-spec a a e summa ized in Table II. They ela e o di e en local o de ings o a oms
in he neighbo hood o he esona ing Fe a oms. The mean alues o he Band δpa ame e s and a
a io o in ensi ies o he second and he i s M¨
ossbaue line, D21, a e p esen ed in Table III. The D21
e lec s he o ien a ion o magne ic momen s in he sample wi h espec o he di ec ion o he γ- ays
and as i ollows om he able i is ma kedly in luenced by echnology.
The spec um o he R sample shown in Fig. 4c di e s om bo h DAM and DIM samples by a
p esence o abou 15% o he pa amagne ic componen ep esen ed by wo double- and one single-line
componen o hype ine pa ame e s; δ= 0.192(4) mm/s, ∆= 0.517(9) mm/s, δ= 0.660(59) mm/s,
∆= 1.831(110) mm/s, o he double s and δ= 0.233(7) mm/s o he single . This pa amagne ic
componen can be, a p esen only specula i ely, asc ibed o chemical and opological su ace dis-
o de and su ace oxida ion. The pa amagne ic componen o med by he double and single o
simila pa ame e s was also obse ed in M¨
ossbaue spec um o he Co2FeAl nanopa icles p epa ed
by co-p ecipi a ion and he mal deoxida ion p ocedu e,14 whe e he su ace phenomena we e aken
in o accoun because o he high su ace a ea o nanopa icles. Ne e heless, con a y o p esen
spec a analysis, he au ho s in Re . 14 ha e de ec ed only one sex uple o hype ine pa ame-
e s, B= 33 T, δ= 0.126 mm/s, and ∆= 0.002 mm/s, asc ibed o a c ys alline e omagne ic
phase.
TABLE II. The hype ine pa ame e s: hype ine induc ion, B; isome shi , δ; ela i e in ensi y, A; o indi idual analyzed
componen .
Comp. 1 2 3 4
Sample B(T) δ(mm/s) A(%) B(T) δ(mm/s) A(%) B(T) δ(mm/s) A(%) B(T) δ(mm/s) A(%)
DAM 31.93 0.042 25.5 30.17 0.043 51.9 29.52 −0.173 9..2 29.37 0.220 13.4
±0.12 ±0.007 ±3.0 ±0.11 ±0.015 ±3.3 ±0.31 ±0.046 ±2.8 ±0.34 ±0.052 ±2.5
DIM 32.78 0.043 4.9 31.23 0.047 45.2 30.26 0.068 40.4 29.14 0.064 9.5
±.18 ±0.011 ±1.0 ±0.09 ±0.002 ±4.0 ±0.13 ±0.003 ±4.0 ±0.18 ±0.008 ±3.2
R31.81 0.017 19.0 30.66 0.031 49.9 29.50 0.040 13.5 27.96 0.003 2.7
±0.05 ±0.003 ±1.6 ±0.02 ±0.002 ±1.4 ±0.09 ±0.005 ±1.0 ±0.21 ±0.002 ±0.6
TABLE III. The mean alues o hype ine pa ame e s; Bmean, δmean, and in ensi y a io, D21, o he second and he i s
M¨
ossbaue line.
Sample Bmean (T) δmean (mm/s) D21
DAM 30.45 ±0.03 0.047 ±0.003 0.315 ±0.009
DIM 30.71 ±0.01 0.057 ±0.007 0.509 ±.005
R 30.65 ±0.01 0.028 ±0.003 0.861 ±0.003
047206-7 Ti o e al. AIP Ad ances 8, 047206 (2018)
FIG. 5. Magne ic hys e esis cu es (a) and Henkel plo s (b) o he a c mel ed, DAM, induc ion mel ed, DIM, and plana low
cas ed, R, samples.
C. Magne ic measu emen s
The bulk hys e esis loops o all samples a e shown in Fig. 5a. The magne ic cha ac e is ics
es ima ed om he measu ed cu es a e summa ized in Table IV. The sa u a ion magne iza ion o he
DAM and DIM samples a e nea ly he same. Howe e , he mo e sensi i e s uc u al pa ame e s, M
and Hc, a e highe o he DAM sample due o dend i es obse ed in g ains o his sample by SEM.
Lowe sa u a ion magne iza ion o he R sample is caused by a highe con en o Al a he expense
o Fe and Co, as con i med by EDX analysis.
The ∆M(H) calcula ed o all samples using equa ion (1) is g aphically ep esen ed as Henkel
plo s in Fig. 5b. They a e nega i e ha is an e idence o p e ailing magne ic dipola (magne os a ic
dipole-dipole) in e ac ions. They a e p oduced by he magne ic momen o each g ain and depend
on he numbe o Fe and Co a oms p esen . The highes in ensi y ∆M(H) = -6.01 Am2/kg, and,
simul aneously, he peak posi ion a e y low magne ic ield o 1.59 kA/m we e ob ained o R
sample. This sample is cha ac e ized by he highes emanence (2.391 Am2/kg) and he low coe ci i y
(0.84 kA/m) alue being be ween hose o he DAM and he DIM sample. The ∆M(H) ob ained o
DAM sample is only sligh ly lowe as compa ed o R sample whe eas he equi ed magne ic ield is
se e al imes highe (see Table IV). The weakes dipola in e ac ions a e obse ed in he DIM sample.
The DAM and DIM samples di e in g ain size and he e o e i is impo an o ake also in o accoun
exchange in e ac ions be ween he neighbo ing g ains which a e de ined as he exchange coupling
o magne ic momen s loca ed a g ain in e ace while he g ains a e in di ec con ac wi h each o he .
Despi e he size o g ains a he DAM and DIM samples being nea ly he same, in he DIM sample
he e ec o exchange coupling is s onge han ha o he magne os a ic in e ac ion. In case o he
DAM sample, i can be specula ed ha he dend i es dec ease he e ec o exchange coupling and
he e o e he dipola in e ac ions p e ail. Simila beha iou was also obse ed o he a c mel ed and
plana low cas ed Co2FeSi samples.24
The su ace hys e esis loops o he DAM sample p esen ed in Fig. 6we e aken om he spo o
abou 300 µm in diame e and pene a ion dep h o abou ens o nm. I was measu ed a he oblique
TABLE IV. Magne ic pa ame e s de i ed om he VSM hys e esis loops: coe ci i y, Hc; sa u a ion, Ms, and emnan , M ,
magne iza ion. Peak posi ion, ∆H, and in ensi y, ∆M, o he Henkel plo s.
Sample DAM DIM R
Ms(Am2/kg) 137.57 138.26 132.82
M (Am2/kg) 1.291 0.860 2.391
Hc(kA/m) 1.30 0.69 0.84
∆H(kA/m) 49.36 25.47 1.59
∆M(Am2/kg) -5.13 -0.98 -6.01
047206-8 Ti o e al. AIP Ad ances 8, 047206 (2018)
FIG. 6. Su ace MOKE hys e esis loops o polished a c mel ed, DAM, sample; a) hys e esis loops in longi udinal con igu a ion
mu ually dis inguished by o a ion o he sample and magne ic ield by 180◦, b) sepa a ed longi udinal and pola magne iza ion
componen s, c) measu ed pola magne iza ion componen a no mal incidence geome y.
inciden angle o 50◦and wi h he magne ic ield applied pa allel o he plane o ligh incidence -
longi udinal con igu a ion (Fig. 6a). A e he loop depic ed by a ull line was measu ed, he sample
and magne ic ield we e o a ed by 180◦and he nex loop (dashed line) was aken om he same
place. Due o he symme y o pe mi i i y enso o cubic c ys al he con ibu ions o he in-plane ML
(longi udinal) and ou -o -plane MP(pola ) magne iza ion componen can be easily dis inguished by
sub ac ing and adding bo h loops om Fig. 6a and di iding by 2. This is shown in Fig. 6b con i ming
he p esence o bo h men ioned magne iza ion componen s. The ou -o -plane MPcomponen yields
as e e e sal and he sa u a ion in he 75 kA/m magne ic ield. On he o he hand, he in-plane ML
componen is no comple ely sa u a ed e en in he maximal applied 125 kA/m magne ic ield. The
shapes and sa u a ion e ec s o magne iza ion componen s may di e in he local sample places
owing o imaging di e en g ains wi h a ious aniso opies unde he lase spo . The second in-plane
magne iza ion componen called ans e sal was sepa a ed in a simila way (no p esen ed), bu i s
con ibu ion was signi ican ly lowe as compa ed o he longi udinal one. The in-plane magne iza ion
componen alls down o ze o a he no mal incidence geome y (Fig. 6c) and he pola componen
eaches i s maximal e ec o 0.44 m ad a abou 75 kA/m magne ic ield. Simila MOKE loops we e
measu ed also o he DIM sample in he p esen s udy and p e iously p esen ed o he Co2FeSi
Heusle alloy in Re . 24.
The hys e esis loop o he R sample measu ed in longi udinal con igu a ion wi h magne ic ield
applied along he ibbon axis is p esen ed in Fig. 7. Co2FeAl ibbon is magne ically so e being
sa u a ed a a ma kedly lowe magne ic ield han DAM and DIM samples. Due o he p epa a ion
echnology and low ibbon hickness (abou 20 µm) he magne iza ion lies in he ibbon plane and
no MPcomponen was de ec ed. The shape and magne ic pa ame e s o he loop a e again s ongly
dependen on he local su ace place illumina ed by he lase spo .
FIG. 7. Longi udinal magne o-op ical hys e esis loop o ibbon, R, sample.