Joule heating as a technique for obtaining uncoupled soft and hard magnetic phases in a Finemet alloy

Joule hea ing as a echnique o ob aining uncoupled so and ha d magne ic phases in a Fineme alloy P. Gup a, A. Gup a, V. F anco, and A. Conde Ci a ion: Jou nal o Applied Physics 101, 033909 (2007); doi: 10.1063/1.2432480 View online: h p://dx.doi.o g/10.1063/1.2432480 View Table o Con en s: h p://sci a ion.aip.o g/con en /aip/jou nal/jap/101/3? e =pd co Published by he AIP Publishing A icles you may be in e es ed in E olu ion o cc Cu clus e s and hei s uc u e changes in he so magne ic Fe85.2Si1B9P4Cu0.8 (NANOMET) and FINEMET alloys obse ed by X- ay abso p ion ine s uc u e J. Appl. Phys. 117, 17A324 (2015); 10.1063/1.4916937 (Fe,Si,Al)-based nanoc ys alline so magne ic alloys o c yogenic applica ions Appl. Phys. Le . 96, 162504 (2010); 10.1063/1.3402775 S uc u al, magne ic, and magne os ic ion beha io s du ing he nanoc ys alliza ion o he amo phous Ni 5 Fe 68.5 Si 13.5 B 9 Nb 3 Cu 1 alloy J. Appl. Phys. 99, 08F104 (2006); 10.1063/1.2162810 E ec o c ys al ac ion on ha dness in FINEMET and NANOPERM nanocomposi e alloys J. Appl. Phys. 97, 10F504 (2005); 10.1063/1.1855173 C ys allog aphic and magne ic p ope ies o nanoc ys alline Fe 78 Al 4 Nb 5 B 12 Cu 1 alloys J. Appl. Phys. 91, 2337 (2002); 10.1063/1.1433932 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02 Joule hea ing as a echnique o ob aining uncoupled so and ha d magne ic phases in a Fineme alloy P. Gup a and A. Gup aa兲 UGC DAE Conso ium o Scien i ic Resea ch, Indo e, MP 452017, India V. F anco and A. Conde Depa amen o Física de la Ma e ia Condensada, ICMSE-CSIC, Uni e sidad de Se illa, P.O. Box 1065, 41080 Se illa, Spain 共Recei ed 1 Ma ch 2006; accep ed 23 No embe 2006; published online 6 Feb ua y 2007兲 A de ailed s udy on he mic os uc u al e olu ion o he Fe73.9Cu0.9Nb3.1Si13.2B8.9 共Fineme 兲alloy upon Joule hea ing and i s co ela ion wi h he magne ic p ope ies is epo ed. Mössbaue spec oscopy sugges s he coexis ence o so nons oichiome ic Fe3Si and ha d i on bo ide magne ic phases. The uncoupled magne ic cha ac e o hese phases is e idenced by dc-hys e esis loop measu emen s. X- ay di ac ion esul s display an excellen ag eemen wi h he magne ic cha ac e iza ion. The magne ic con ibu ion o he so phase has been dec eased om 70% o 10% wi h inc easing annealing cu en and ime. The swi ching ield alue o he so magne ic phase is 50 A/m, which is e y less as compa ed o 2000 A/m, o he ha d magne ic phase. Exis ence o uncoupled so and ha d magne ic phases makes hese sys ems sui able o use as magne ic labels. ©2007 Ame ican Ins i u e o Physics.关DOI: 10.1063/1.2432480兴 I. INTRODUCTION Amo phous ma e ials a e widely used in senso s and se- cu i y sys ems. Magne ic labels making use o amo phous ibbons a e common in he ma ke and hey a e used as a me chandise p o ec ion. The mel -spun FeSiB amo phous al- loy ibbon wi h small amoun o Cu and Nb, comme cially known as Fineme alloy, also exhibi s gian magne oimped- ance 共GMI兲e ec , and hus ha e po en ial applica ions as minia u e magne ic ield senso s.1 The e a e nume ous esul s in he li e a u e ega ding he c ys alliza ion beha io o Fineme - ype alloys, ei he p o- duced by con en ional u nace annealing o by Joule hea ing, and i s co ela ion o magne ic p ope ies.2,3The de i i ica- ion p ocess in hese alloys akes place in wo main s ages. The i s one is associa ed wi h he appea ance o he nano- c ys alline Fe 共Si兲phase embedded in he emaining e o- magne ic amo phous ma ix, while he second s age co e- sponds o he appea ance o bo ide- ype phases wi h ec ys alliza ion phenomena. Nanoc ys alline samples wi h an op imal c ys alline ac ion a e e en so e han hei amo phous p ecu so s due o he exchange coupling be ween he nanoc ys als, ansmi ed by he e omagne ic ma ix.4,5 The beginning o he second c ys alliza ion s age causes an ab up magne ic ha dening o he ma e ial due o he high magne oc ys alline aniso opy o he bo ide- ype phases.2,6–8 The amo phous- o-nanoc ys alline ans o ma ion is s ic ly ela ed o he hea ing a e a which he ans o ma ion is induced.9Nanoc ys alliza ion ende s hese alloys ex- emely b i le. This limi s hei p ac ical applica ion in ans- o me co es, e c. Recen ly, i has been shown ha he so- called dc Joule hea ing echnique p oduces he amo phous o nanoc ys alline ans o ma ion o occu wi hou signi ican emb i lemen o he specimen.10 This echnique consis s o applying an elec ical cu en o he specimen o a ew sec- onds 共hea ing a e ⬃100 K/s兲and exploi s he Joule hea eleased o he sample o induce he c ys alliza ion p ocess. This echnique can be pe o med in ai wi hou a s ong oxi- da ion o he specimens and has been epo ed o be used as an excellen p ocedu e o achie e op imum magne ic p ope - ies in me allic glasses.11,12 One o he peculia i ies o Joule hea ed samples is ha hey p esen a ine mic os uc u e han con en ionally an- nealed ones, causing he mode a e magne ic ha dening e- la ed o he onse o nanoc ys alliza ion o be less de ec able and he ha dening associa ed wi h he second s age less ab up .13 Mul iphase ma e ials exhibi ing so and ha d zones, ha is, wi h a hys e esis loop whose ield de i a i e shows a i- ous peaks 共commonly e e ed in he li e a u e as ma e ials showing a ious coe ci i ies兲we e poin ed ou o be s ong candida es o be used as a magne ic label wi h he big ad- an age o being a single ma e ial.14–16 The aim o his wo k is o s udy he possibili y o ob aining a so +ha d magne ic composi e in a Fineme alloy by p ope ly selec ing he Joule- hea ing pa ame e s 共cu en and ime兲. Fo ha pu pose, he nanoc ys alliza ion o amo phous Fe73.9Nb3.1Cu0.9Si13.2B8.9 ibbons induced in a con olled way by Joule hea ing in ai is analyzed in de ail using he x- ay di ac ion 共XRD兲and Mössbaue spec oscopy echniques. The magne ic p ope ies a e de e mined om dc hys e esis loops and co ela ed wi h he mic os uc u al cha ac e is ics o he ma e ial. II. EXPERIMENT The p esen s udy was pe o med on amo phous ibbons o composi ion Fe73.9Nb3.1Cu0.9Si13.2B8.9, which we e p o- duced by apid quenching and kindly supplied by D . P. Du- haj, Sol ak epublic. Joule hea ing was made by passing a a兲Elec onic mail: agup a@cs .e ne .in JOURNAL OF APPLIED PHYSICS 101, 033909 共2007兲 0021-8979/2007/101共3兲/033909/6/$23.00 © 2007 Ame ican Ins i u e o Physics101, 033909-1 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02 cons an dc h ough he sample. The samples we e ixed a sample holde by i s ex emi ies using b ass clamps 共hea sinks兲a which he cu en sou ce is connec ed h ough a ime . The se up allows o use specimens o di e en leng hs by adjus ing he b ass clamps. In he p esen s udy Joule hea ing was made on he specimens ha ing iden ical size 共7cm⫻1cm⫻18 ␮ m兲. The c oss sec ion is a undamen al pa ame e in he Joule hea ing p ocedu e, since i de e mines he o al dissipa ed powe du ing he annealing. Annealings we e done a cons an cu en s o 6.2, 7.0, and 7.8 A o di e en imes o ob ain se ies o samples a di e en s ages o c ys alliza ion. The es ima e o he eal empe a u e o he sample du ing Joule hea ing is a complex p oblem17 as i is a noniso he mal ea men and he sho e ec i e ime neces- sa y o cause he main s uc u al ans o ma ions 共gene ally a ew seconds兲b ings es ic ions on di ec me hods o em- pe a u e measu emen . Thus in he p esen wo k he di e en c ys alliza ion s ages a e ea ed as dependen on he anneal- ing pa ame e s 共cu en and ime兲, ins ead o he empe a u e o he sample. X- ay di ac ion measu emen s we e pe o med using Cu K ␣ cha ac e is ic adia ion om a Rigaku o a ing anode gene a o . A cu ed c ys al di ac ed beam monoch oma o was used o elimina e he i on luo escence adia ion. In o de o ge in o ma ion abou he magne ic p ope ies o he specimens oom- empe a u e Mössbaue measu e- men s we e made using a 57Co:Rh sou ce in ansmission geome y. The ob ained spec al p o iles we e analyzed by means o a cu en minimiza ion ou ine, e e ing he eloc- i y scale and he isome shi s o me allic i on. Quasis a ic M-Hhys e esis loops we e measu ed a oom empe a u e o all he as-quenched and Joule hea ed samples using a quasis a ic loop ace desc ibed elsewhe e,18 applying a maximum ield o 7 kA/m. Due o he speci ic design o his equipmen , he i s de i a i e o he magne iza ion cu e is di ec ly measu ed. III. RESULTS AND DISCUSSION A. XRD measu emen s Figu e 1shows selec ed XRD spec a, illus a ing he mic os uc u al e olu ion o he samples as a unc ion o annealing cu en and ime. The as-quenched specimen p e- sen ed a b oad hump, which is cha ac e is ic o he ypical amo phous phase ha can be i ed by a Lo en zian unc ion wi h ull wid h a hal maximum o 5.44° ±0.04°. XRD pa - e ns o he annealed specimens show ha a e ea men wi h cu en o 6.2 A 共which is he lowes cu en used o he p esen s udies兲 o 180 s he specimen becomes c ys al- line and comp ises o nons oichiome ic DO3Fe3Si phase as indica ed by sha p peaks a 2 ␪ alues o 27.3°, 45.1°, 65.6°, and 83.3° wi h some small indica ion o amo phous phase.19 The line b oadening o he c ys alline componen was hen used o de e mine he a e age g ain size o he nons oichio- me ic Fe3Si phase. The posi ion o he c ys alline peaks co - esponding o nons oichiome ic Fe3Si phase emains nea ly unchanged o he whole ange o annealing cu en 共6.2 A ⬍I⬍7.8 A兲. A e annealing a 7 A o 10 s, he peak co esponding o 共220兲 e lec ion o nons oichiome ic Fe3Si phase becomes sha pe , showing no e idence o he emaining amo phous phase. The addi ional peaks a 43.4°, 50.4°, 73.7°, and 80.2° s a appea ing which co espond o Fe2B phase20 whe eas peaks a 38.4°, 44.1°, and 53.7° co espond o Fe3B phase and peaks a 44.1° and 50.3° a e ins uc i e o Fe23B6 phase.21 XRD pa e n o specimen a e annealing a highes cu en o 7.8 A o 90 s also shows signa u e o coexis ence o ha d magne ic i on bo ide phases 共Fe2B, Fe3B, and Fe23B6兲along wi h so magne ic nons oichiome ic Fe3Si phase. Some o he uniden i ied XRD lines could co espond o oxide phases, as he ibbons we e annealed in ai . Since XRD measu emen s we e done in e lec ion geome y he con i- bu ion o su ace oxides is expec ed o be enhanced. In o de o ob ain he la ice pa ame e and pa icle size o he nons oichiome ic Fe3Si phase, Rie eld analysis o he annealed samples assuming only nons oichiome ic Fe3Si phase 共i.e., peaks a 27.3°, 45.1°, 65.6°, and 83.3° only we e i ed兲ha e been done. The la ice pa ame e is indeed changing om 5.67 o 5.69 Å as we go on inc easing he annealing cu en ; i may be due o some composi ional changes in he nons oichiome ic Fe3Si phase. In ac , a de- c ease in Si con en could be associa ed wi h an inc ease in la ice pa ame e .22 Assuming pseudo-Voig line p o iles ull wid h a hal maximum 共FWHM兲o he maximum in ensi y peak 共nons o- ichiome ic Fe3Si phase兲in all he samples has been calcu- la ed using he o mula o Caglio i e al.23 The c ys alli e size o his phase has been calcula ed by means o Sche e o mula24 using peak posi ion and FWHM o he sha pes peak. The c ys alli e size a e annealing a 6.2 A o 180 s is 10.4±0.2 nm which goes on inc easing wi h annealing cu - en and eaches o 27.4±0.1 nm a e annealing a 7.8 A o 90 s. FIG. 1. Some ep esen a i e XRD pa e ns o he specimen Fe73.9Cu0.9Nb3.1Si13.2B8.9 a e annealing a 6, 7, and 7.8 A o di e en imes; uniden i ied peaks co espond o oxide phases as he ibbons we e annealed in ai only. Fo compa ison XRD pa e n o he as p epa ed spec a is also shown. 033909-2 Gup a e al. J. Appl. Phys. 101, 033909 共2007兲 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02 B. Hys e esis loop measu emen s The coe ci i y o he as-cas specimen is ⬃18 A/m, a ypical alue o his kind o alloys be o e s ess elaxa ion. Upon Joule hea ing o he selec ed cu en s and imes, hys- e esis loops p esen e idences o he coexis ence o di e en uncoupled magne ic phases 共Fig. 2兲, as indica ed by he ac ha he loops could be decomposed in wo addi i e loops wi h di e en coe ci i ies. Taking in o accoun he p e i- ously desc ibed mic os uc u e, he so magne ic phase should be asc ibed o he nons oichiome ic Fe3Si nanoc ys- als, while he ha d phase should be associa ed wi h he bo ide- ype phases. In o de o disca d he in luence o he clamps a bo h ends o he sample on he exis ence o he so magne ic phase, measu emen s we e epea ed a e emo ing 1 cm o he samples a bo h ends, ob aining he same esul s. Figu e 3p esen s he e olu ion o he coe ci i y o he majo loops, Hc, educed emanence, M /Ms, and mean g ain size o he nons oichiome ic Fe3Si phase, 具D典, as a unc ion o annealing condi ions. The p og essi e inc ease in coe ci i y upon annealing is no co ela ed o he mean g ain size o he Fe–Si nanopa icles, bu o he inc easing ac ion o bo ide- ype phases, which in he magne ic measu emen s can be es ima ed om he ela i e impo ance o he di e en peaks in he de i a i e o he magne iza ion cu e 共Fig. 4兲. In pa - icula , he sample hea ed a 7.8 A o 12 s p esen s a smalle c ys alli e size han he sample annealed a 7 A o 50 s, al hough coe ci i y beha io is he opposi e, in ag eemen wi h he inc easing ac ion o bo ide phases e idenced by mic os uc u al and magne ic esul s. Fo he annealing a highe cu en s and imes, he hys e esis loops e idence he magne ic coupling be ween he di e en phases, wi h he dis- appea ance o he low- ield peak in he ield de i a i e o he magne iza ion cu e. In o de o make an es ima ion o he ela i e con ibu- ions o magne iza ion a ising om he so and ha d phases, a phenomenological app oach can be used. I he loops p e- sen ed pla eaus o magne iza ion o ield alues close o he coe ci i y o he so phase, he M /MScould ha e been used o his es ima ion. Howe e , al hough he e is a no able change in slope close o he coe ci i y o he so phase, a ho izon al pla eau is no ound. Consequen ly, an al e na i e me hod, based on a phenomenological i ing o he magne- iza ion cu es, has been used. Figu e 5 ep esen s a i o he FIG. 2. 共Colo online兲The e olu ion o hys e esis loops wi h inc easing annealing cu en . FIG. 3. Dependence on he annealing condi ions o he coe ci i y, educed emanence, and Fe,Si phase mean g ain size o he s udied samples. FIG. 4. 共Colo online兲Field de i a i e o he magne iza ion cu e 共second quad an 兲o all samples. Ve ical displacemen is included o a oid he o e lapping o he cu es. FIG. 5. 共Colo online兲Fi o he no malized magne iza ion cu e co e- sponding o sample annealed a 7 A o 12.5 s wi h wo pseudo-Voig unc ions. 033909-3 Gup a e al. J. Appl. Phys. 101, 033909 共2007兲 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02 no malized magne iza ion cu e wi h wo pseudo-Voig unc- ions. One ep esen s he uncoupled so magne ic phase; he o he , he ha d con ibu ions 共only one i ing has been p e- sen ed as an example兲. As he loops we e p e iously no mal- ized, he o al a ea unde he cu e should be 2. The e o e, he a ea o he so peak di ided by 2 co esponds o he ac ion o magne iza ion eme ging om he uncoupled so phase. I he sa u a ion magne iza ion o all phases we e he same, his would co espond o he olume ac ion o he so phase. The so phase is i ed mo e accu a ely han he ha d con ibu ion. This can be due o he di e si y o bo ide phases p esen in he sample and o he mo e han p obable di e ences in hei coupling. Howe e , as he ele an pa- ame e is he ac ion o so phase and he o al cu e a ea is no malized, he nonpe ec i ing o he ha d con ibu ion is no a eal di icul y o he es ima ion. F om he ela i e a ea o he “so peak,” i s con ibu ion o he o al magne iza ion can be es ima ed 共Fig. 6兲. I should be no ed ha we e e o an uncoupled so phase, bu no o he nons oichiome ic Fe3Si nanoc ys als. Fo su e he e a e nons oichiome ic Fe3Si nanoc ys als in he samples abo e 7 A 50 s, bu hey canno be decon olu ed om he magne- iza ion cu es, indica ing ha he phase is coupled o he ha d magne ic phase. Rega ding he swi ching ields o he phases, hey can be es ima ed om he peaks in he ield de i a i es o magne i- za ion. Fo he so phase, i s alue emains ai ly cons an wi h cu en annealing 共Fig. 7兲. Howe e , he posi ion o he peak o he ha d phases does no ollow a clea end. This can be due o he di e en bo ide- ype phases p esen in he samples and o hei di e en coupling among hem. Wi h espec o he e olu ion o he educed emanence, i is in ag eemen wi h ha ound o con en ionally an- nealed Fineme - ype alloys.25 Fo he annealing a he high- es cu en s, i ends o 0.85, which is cha ac e is ic o an- domly o ien ed cubic pa icles.26 Taking in o accoun ha he only cubic phases iden i ied in he mic os uc u al analysis a e nons oichiome ic Fe3Si and Fe23B6, hey should be e- sponsible o he magne ic beha io o he mo e c ys allized samples, al hough o he bo ide phases wi h uniaxial aniso- opy a e also p esen . Fineme alloy, u nace annealed a di e en empe a- u es, did no exhibi uncoupled magne ic phases, he eason being as ollows: The so /ha d uncoupled beha io is ex- pec ed o be obse ed when he olume ac ion o bo h so 共Fe–Si兲and ha d 共Fe–B兲magne ic phases is small, so ha he coupling among hem is weak. In cu en annealed samples he sample empe a u e ises o such a high alue ha bo h nons oichiome ic Fe3Si and Fe–B phases 共i.e., i s and sec- ond s ages o c ys alliza ion兲s a o ming almos simul a- neously, and by con olling he annealing ime hei olume ac ions can be con olled. On he o he hand in he u nace annealed samples, whe e annealing imes a e gene ally la ge and annealing empe a u es a e no e y high, ini ially he i s s age o c ys alliza ion only is comple ed and hen only he second s age s a s. The e o e, i is di icul o ealize a si ua ion whe e bo h he phases a e p esen in small quan i- ies. C. Mössbaue measu emen s The Mössbaue spec oscopy, a echnique based on hy- pe ine in e ac ions, p o ides in o ma ion abou local neigh- bo hood o ce ain p obe si es and can dis inguish la ice si es, which a e a omically, elec onically, o magne ically inequi alen . The wid h o hype ine ield dis ibu ion o Mössbaue spec um depends mainly on he chemical sho - ange o de , hus i can be u ilized o iden i y phases whose dimensions a e oo small o XRD measu emen s. In he p esen s udy, he i ing o he Mössbaue spec a has been pe o med using he NORMOS p og am, which al- lows a simul aneous i o se e al c ys alline spec a wi h possible addi ion o an amo phous phase. The specimen is cha ac e ized by a dis ibu ion o hype ine ields.27 Figu es 8and 9show espec i ely, Mössbaue spec um o as-quenched specimen and some ep esen a i e Möss- baue spec a o he specimen annealed o 6.2, 7, and 7.8 A o di e en imes. The as-quenched specimen consis s o a b oad sex e ypical o amo phous phase 共Fig. 8兲; he spec- um has been analyzed in e ms o a dis ibu ion o hype - ine ields ep esen ing he dis ibu ion o local en i onmen a ound he Fe a oms. As indica ed om he inse o he Fig. 8, he hype ine ield dis ibu ion consis s o wo b oad humps. The smalle hump a ound BHF 共magne ic hype ine FIG. 6. Con ibu ion o he so magne ic phase wi h inc easing annealing cu en and ime. FIG. 7. 共Colo online兲Plo o swi ching ields co esponding o each phase o all he samples. 033909-4 Gup a e al. J. Appl. Phys. 101, 033909 共2007兲 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02 ield兲=10 T ep esen s he Fe a oms ha ing Nb nea neigh- bo s. I is known ha he p esence o Nb in he i s coo di- na ion shell o Fe signi ican ly educes he hype ine ield o Fe a oms. The Mössbaue spec a o he annealed specimens show clea e idence abou he c ys alliza ion 共Fig. 9兲. Thus he spec a a e c ys alliza ion we e bes i ed by i e o e lap- ping sex e s: a b oad sex e co esponding o he emaining amo phous phase and ou ela i ely sha p sex e s indica ing he exis ence o i e dis inc Fe si es. The i ing o he Mössbaue spec a o he sample an- nealed a 6.2 A o 180 s yields ollowing in o ma ion: 共i兲Abou 35% o he Fe is in he amo phous phase. 共ii兲Simul aneous p esence o he hype ine ield compo- nen s o 31.3±0.1, 24.2±0.2, and 27.8±0.2 T sug- ges s ha he nons oichiome ic Fe3Si phase is a pa - ially o de ed DO3s uc u e.28 The spec um has been i ed closely by he in e nal magne ic ield, BHF alue o 11.7 T o he one c ys alline sex e , which co esponds o ␤ -FeB phase.29 O he c ys alline sex- e s i ed well wi h he BHF alue o 31.3±0.1, 24.2±0.2, and 27.8±0.2 T co espond o pa ially o de ed nons oichio- me ic Fe3Si DO3phase. I is impo an o no e ha pa ially o de ed and nons oichiome ic phase is associa ed wi h he ield alues o 20.1, 31.0, 24.3, and 28.5 T.28 A e annealing o a highe cu en o 7 A o 10 s he specimen consis s o Fe3Si and Fe–B phases wi h a c ys al- line ac ion o ⬃61.9%. Howe e , he spec um has been bes i ed wi h c ys alline sex e s ha ing in e nal magne ic ield BHF o 32.1±0.1, 28.8±0.1, 24.6±0.1, and 11.6±0.1 T co esponding o Fe3Si, Fe3B, Fe2B/Fe23B6, and FeB phases, espec i ely.30–32 I is impo an o no e ha ield alues 28.8 and 24.6 T which co esponds o Fe3B and Fe2B/Fe23B6ha d magne ic phases, a e close o ha o Fe3Si phase. These o e lapping ield alues sugges ha he phase may be ei he Fe3Si phase o Fe2B/Fe23B6phase. Bu he addi ional ield con ibu ion o 11.6 T gi es clea indica ion o he p esence o Fe–B phase. The p esence o all he men ioned phases is s ill ob- se ed a e annealing a 7.8 A o 90 s 共highes cu en used in he p esen s udy兲, wi h a c ys alline ac ion ⬃64.4%, hus he specimen is s ill ha ing di e en magne ic phases. Howe e , he dc hys e esis measu emen s show ha a e annealing a 7.8 A he loops a e ha ing single coe ci i y, al hough he sample s ill has bo h he silicide as well as bo ide phases. These esul s can be unde s ood by conside - ing ha he single high coe ci e loop a e annealing a 7.8 A is a esul o exchange coupling be ween he phases. As depic ed by Mössbaue measu emen s, he coexis - ence o bo ide phases 共Fe2B, Fe3B, and Fe23B6兲and Fe3Si phase has also been con i med wi h XRD measu emen s. Howe e , he p esence o Fe–B ha d magne ic phase has no been de ec ed h ough XRD measu emen while Mössbaue measu emen s also suppo s he p esence o he same in all he annealed specimens. I may be due o smalle dimension o Fe–B ha d magne ic phase o XRD measu emen s.33 IV. CONCLUSIONS The c ys alliza ion p ocess o he Fe73.9Cu0.9Nb3.1Si13.2B8.9 specimen p oduced by Joule hea - ing has been s udied by means o x- ay di ac ion, Möss- baue spec oscopy, and dc-hys e esis loop measu emen s. Co ela ion be ween s uc u al and magne ic measu emen s has been ound. Fo he selec ed annealing cu en s and imes, he samples a e comp ised o nons oichiome ic Fe3Si nanoc ys als and bo ide- ype phases 共FeB, Fe2B, Fe3B, and Fe23B6兲, as iden i ied by XRD and Mössbaue spec oscopy. Thei magne ic beha io is cha ac e is ic o a composi ion o uncoupled so and ha d magne ic phases. This ea u e can be FIG. 8. Room empe a u e Mössbaue spec um o he as-quenched Fe73.9Cu0.9Nb3.1Si13.2B8.9 alloy; inse shows co esponding hype ine ield dis ibu ion. FIG. 9. Some ep esen a i e oom empe a u e Mössbaue spec a o Fe73.9Cu0.9Nb3.1Si13.2B8.9 alloy joule hea ed a 共i兲6.2 A o 180 s, 共ii兲7A o 10s,and共iii兲7.8 A o 90 s. 033909-5 Gup a e al. J. Appl. Phys. 101, 033909 共2007兲 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02 applied o he p oduc ion o magne ic labels. In he case o con en ional u nace annealing, ini ially he i s s age o c ys alliza ion is comple ed and hen only he second s age s a s, he e o e i is di icul o ealize he si ua ion whe e bo h he phases a e p esen in compa able quan i ies. ACKNOWLEDGMENT One o he au ho s 共P. Gup a兲would like o hank CSIR, New Delhi, o inancial suppo in he o m o senio e- sea ch ellowship. 1Z. C. Wang, F. F. Gong, X. L. Yang, L. Zeng, G. Chen, J. X. Yang, S. M. Qian, and D. P. Yang, J. Appl. Phys. 87, 4819 共2000兲. 2Y. Yoshizawa, S. Oguma, and K. Yamauchi, J. Appl. Phys. 64, 6044 共1988兲. 3M. E. McHen y, M. A. Willa d, and D. E. Laughlin, P og. Ma e . Sci. 44, 291 共1999兲. 4G. He ze , IEEE T ans. Magn. 25,3327共1989兲. 5A. He nando, M. Vázquez, T. Kulik, and C. P ados, Phys. Re . B 51, 3581 共1995兲. 6P. Go ia, J. S. Ga i aonandia, and J. M. Ba andia an, J. Phys.: Condens. Ma e 8,5925共1996兲. 7N. Ka aoka, A. Inoue, T. Masumo o, Y. Yoshizawa, and K. Yamauchi, Jpn. J. Appl. Phys., Pa 1 28,1820共1989兲. 8T. Kulik and A. He nando, Ma e . Sci. Fo um 179, 587 共1995兲. 9P. Allia, M. Knobel, M. Ba icco, P. Tibe o, and F. Vinai, J. Magn. Magn. Ma e . 133,243共1994兲. 10S. S. Yoon, S. C. Yu, G. H. Ryu, and C. G. Kim, J. Appl. Phys. 85, 5432 共1999兲. 11T. Jagielinski, IEEE T ans. Magn. 19,1925共1983兲. 12J. M. Ba andia aán, A. He nando, and O. V. Nielsen, IEEE T ans. Magn. 62, 1964 共1986兲. 13R. Houssa, V. F anco, and A. Conde, J. Magn. Magn. Ma e . 203, 199 共1999兲. 14C. Radelo , G. Rausche , and H. Wa limon , U.S. Pa en No. 4,950,550 共21 Augus 1990兲. 15C. Mo on, C. A oca, M. C. Sanchez, A. Ga cia, and E. Lopez, IEEE T ans. Magn. 31, 906 共1995兲. 16J. P. Sinnecke , P. Tibe o, M. Vázquez, and A. He nando, J. Appl. Phys. 82, 5871 共1997兲. 17P. Allia, M. Ba icco, M. Knobel, P. Tibe o, and F. Vinai, Ma e . Sci. Eng., A179,361共1994兲. 18V. F anco, J. Ramos-Ma os, and A. Conde, Re . Sci. Ins um. 67, 4167 共1996兲. 19K. Keil, J. L. Be kly, and L. H. Fuchs, Am. Mine al. 67,126共1982兲. 20In e na ional cen e o di ac ion da a PDF-2 Da abase, 2002. 21U. He old and U. Kos e , Z. Me allkd. 69, 326 共1978兲. 22W. P. Pea son, Handbook o La ice Spacings and S uc u es o Me als 共Pe gamon, Ox o d, 1967兲. 23G. Caglio i, A. Paole i, and F. P. Ricci, Nucl. Ins um. 3,223共1958兲. 24B. D. Culli y, Elemen s o X- ay Di ac ion 共Addison-Wesley, Reading, MA, 1978兲. 25V. F anco, C. F. Conde, and A. Conde, J. Magn. Magn. Ma e . 185,353 共1998兲. 26S. Chikazumi, Physics o Magne ism 共K iege , Malaba , 1978兲,p.249. 27R. A. B and, J. Laue , and D. M. He lach, J. Phys. F: Me . Phys. 14, 555 共1984兲. 28A. Gup a e al., In e me allics 8, 287 共2000兲. 29T. Shiajo, F. I ak, H. Takaki, Y. Nakamu a, and N. Shikagono, J. Phys. Soc. Jpn. 19, 1252 共1964兲. 30W. K. Choo and R. Kaplow, Me all. T ans. A 8A, 417 共1977兲;G.L.Cae and J. M. Dubois, Phys. S a us Solidi A 64,275共1981兲. 31L. Takacs, M. C. Cade ille, and I. Vincze, J. Phys. F: Me . Phys. 5,800 共1975兲. 32H. F anke, U. He old, U. Kos e , and M. Rosenbe g, in Rapidly Quenched Me als III, edi ed by B. Can o 共Chameleon, London, 1978兲,p.155. 33F. H. Sanchez, J. I. Budnick, Y. D. Zhang, W. A. Hines, and M. Choi, Phys. Re . B 34, 4738 共1986兲. 033909-6 Gup a e al. J. Appl. Phys. 101, 033909 共2007兲 [This a icle is copy igh ed as indica ed in he a icle. Reuse o AIP con en is subjec o he e ms a : h p://sci a ion.aip.o g/ e mscondi ions. Downloaded o ] IP: 150.214.182.17 On: Thu, 21 Jan 2016 17:11:02