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Iyo magineti zvimiro zveSrFe12O19 (SFO) yakaoma hexaferrite inodzorwa nehukama hwakaoma hweiyo microstructure, iyo inotaridza kukosha kwavo kune zvechigarire magineti application.Sarudza boka reSFO nanoparticles rinowanikwa ne-sol-gel inongoerekana yaita combustion synthesis, uye ita zvakadzama maitiro e-X-ray powder diffraction (XRPD) maitiro neG (L) mutsara weprofile analysis.Iyo yakawanikwa crystallite saizi yekugovera inoratidza kutsamira kuri pachena kwehukuru pamwe ne [001] kutungamira pane synthesis nzira, zvichiita kuti pave nekuumbwa kwemakristallite asina kujeka.Mukuwedzera, ukuru hweSFO nanoparticles hwakatemerwa nekutapurirana electron microscopy (TEM) kuongororwa, uye avhareji yenhamba yemakristallite muzvikamu zvakafungidzirwa.Mhedzisiro iyi yakaongororwa kuratidza kuumbwa kwenzvimbo imwe chete pasi peiyo yakakosha kukosha, uye iyo activation vhoriyamu inotorwa kubva kunguva-inotsamira magineti kuyerwa, yakanangana nekujekesa reverse magnetization maitiro ezvakaoma magineti zvinhu.
Nano-scale magineti zvinhu zvine hukuru hwesainzi uye tekinoroji kukosha, nekuti iwo magineti maitiro anoratidza maitiro akasiyana zvakanyanya zvichienzaniswa nehukuru hwevhoriyamu, izvo zvinounza maonero matsva nemashandisirwo1,2,3,4.Pakati pezvishandiso zvenanostructured, M-mhando hexaferrite SrFe12O19 (SFO) yave mukwikwidzi anoyevedza wekusingaperi magineti application5.Muchokwadi, mumakore achangopfuura, basa rakawanda rekutsvagisa rakaitwa pakugadzirisa SFO-yakavakirwa zvinhu pane nanoscale kuburikidza nemhando dzakasiyana dzekubatanidza uye nzira dzekugadzirisa kukwirisa saizi, morphology, uye magineti zvinhu6,7,8.Pamusoro pezvo, yakagamuchira kutarisisa kukuru mukutsvagisa uye kusimudzira kwekuchinjana coupling masisitimu9,10.Yayo yakakwira magnetocrystalline anisotropy (K = 0.35 MJ/m3) yakanangana neiyo c-axis yehexagonal lattice yayo 11,12 ndiyo yakananga mhedzisiro yekubatana kwakaoma pakati pemagineti uye chimiro chekristaro, crystallites uye saizi yezviyo, morphology uye magadzirirwo.Naizvozvo, kudzora hunhu huri pamusoro apa hwaro hwekusangana nezvinodiwa chaizvo.Mufananidzo 1 unoratidza iyo yakajairika hexagonal space boka P63/mmc yeSFO13, uye ndege inoenderana nekuratidzwa kweiyo mutsara profil yekuongorora kudzidza.
Pakati pezvinhu zvakabatana zve ferromagnetic particle size reduction, kuumbwa kwenzvimbo imwe chete pasi pehuwandu hunokosha hunoita kuti kuwedzerwa kwemagineti anisotropy (nekuda kwenzvimbo yakakwirira kusvika kuhuwandu hwehuwandu), iyo inotungamirira kumunda unomanikidzira14,15.Iyo nzvimbo yakafara pazasi peyakakosha dimension (DC) mumidziyo yakaoma (yakajairika kukosha ingangoita 1 µm), uye inotsanangurwa neinonzi coherent size (DCOH)16: izvi zvinoreva nzira diki yevhoriyamu ye demagnetization muhukuru hwakabatana. (DCOH) , Inoratidzwa sehuwandu hwekugadzirisa (VACT) 14. Zvisinei, sezvakaratidzwa muMufananidzo 2, kunyange zvazvo ukuru hwekristini huduku kudarika DC, inversion process inogona kunge isingaenderani.Mune nanoparticle (NP) zvikamu, iyo yakakosha vhoriyamu yekudzokera kumashure inoenderana neiyo magineti viscosity (S), uye yayo magineti kutsamira inopa ruzivo rwakakosha nezve switching process yeNP magnetization17,18.
Pamusoro: Schematic dhayagiramu yekushanduka kwenzvimbo yekumanikidza ine particle size, inoratidza inoenderana magnetization reversal process (yakagadziriswa kubva ku15).SPS, SD, uye MD inomiririra superparamagnetic state, single domain, uye multidomain, zvichiteerana;DCOH uye DC anoshandiswa dhayamita yekubatana uye yakakosha dhayamita, zvichiteerana.Pazasi: Zvitsvedzero zvezvimedu zvehukuru hwakasiyana, zvichiratidza kukura kwekristaro kubva kune imwechete crystal kusvika ku polycrystalline.uyeratidza crystallite uye particle size, zvichiteerana.
Nekudaro, pane iyo nanoscale, mitsva yakaoma maficha yakaunzwa, senge yakasimba magineti kupindirana pakati pezvimedu, saizi kugovera, particle shape, surface disorder, uye kutungamira kweiyo nyore axis yemagnetization, izvo zvese zvinoita kuti kuongororwa kuome19, 20 .Izvi zvinhu zvinokanganisa zvakanyanya kugoverwa kwesimba chipingamupinyi uye unofanirwa kunyatsotariswa, nekudaro zvichikanganisa iyo magnetization reversal mode.Pahwaro uhwu, zvinonyanya kukosha kunyatsonzwisisa kuwirirana pakati peiyo magineti vhoriyamu uye yemuviri nanostructured M-mhando hexaferrite SrFe12O19.Nokudaro, semuenzaniso wemuenzaniso, takashandisa seti yeSFOs yakagadzirwa nechepasi-up sol-gel nzira, uye ichangobva kuita tsvakurudzo.Mhedzisiro yapfuura inoratidza kuti ukuru hwemakristallite huri mu nanometer range, uye iyo, pamwe chete nechimiro chekristallites, zvinoenderana nekupisa kunoshandiswa.Mukuwedzera, iyo crystallinity yemasampuli akadaro inoenderana neiyo nzira yekubatanidza, uye yakawedzera ongororo yekuongorora inodiwa kujekesa hukama pakati pekristallite uye saizi yechikamu.Kuti tiratidze hukama uhwu, kuburikidza nekutapurirana electron microscopy (TEM) ongororo yakasanganiswa nenzira yeRietveld uye mutsara ongororo yehuwandu hwehuwandu hweX-ray hupfu diffraction, kristaro microstructure paramita (kureva, crystallites uye particle size, chimiro) zvakanyatsoongororwa. .XRPD) maitiro.Chimiro chechimiro chine chinangwa chekuona hunhu hweanisotropic hweanowanikwa nanocrystallites uye kuratidza kugona kwekuongororwa kwemutsara senzira yakasimba yekuratidza kukwidziridzwa kwepamusoro kune nanoscale range ye (ferrite) zvinhu.Inowanikwa kuti vhoriyamu-inorema crystallite saizi yekugovera G (L) yakasimba zvinoenderana nekristaro kutungamira.Mubasa iri, isu tinoratidza kuti hunyanzvi hwekuwedzera hunodiwa zvechokwadi kuburitsa zvine chekuita nehukuru-maparamita kuti unyatso kutsanangura chimiro uye magineti maitiro emasampuli ehupfu akadaro.Iyo nzira yekudzosera magineti yakadzidzwawo kujekesa hukama pakati pe morphological chimiro maitiro uye magineti maitiro.
Rietveld kuongororwa kwe-X-ray powder diffraction (XRPD) data inoratidza kuti ukuru hwekristallite pamwe chete ne-c-axis inogona kugadziriswa nekurapa kwakakodzera kwekupisa.Zvinonyatsoratidza kuti kuwedzera kwepamusoro kwakaonekwa mumuenzaniso wedu kungangove kuri nekuda kweiyo anisotropic crystallite chimiro.Pamusoro pezvo, kuwirirana pakati peavhareji yedhayamita yakaongororwa naRietveld uye iyo Williamson-Hall diagram (uyemuTable S1) inoratidza kuti makristallite anenge asina kunetsa uye hapana kuumbwa kwemaitiro.Iko kushanduka kweiyo crystallite saizi yekugovera munzira dzakasiyana inoisa pfungwa dzedu pane yakawanikwa saizi.Ongororo yacho haisi nyore, nekuti sampuli inowanikwa ne-sol-gel inongoerekana yapisa inoumbwa neagglomerates yezvimedu zvine porous chimiro6,9, makumi maviri nerimwe.TEM inoshandiswa kudzidza chimiro chemukati cheyedzo sampuli mune zvakadzama.Yakajairika mifananidzo yakajeka inoshumwa muMufananidzo 3a-c (kune tsananguro yakadzama yekuongorora, ndapota tarisa kune chikamu 2 chezvinyorwa zvekuwedzera).Sample ine zvidimbu zvine chimiro chezvidimbu zvidiki.Iwo maplatelet anobatana kuti aumbe porous aggregates ehukuru hwakasiyana uye maumbirwo.Kuti tifungidzire saizi yekugovera maplatelet, nzvimbo yezvikamu zana zvesample yega yega yakayerwa nemaoko uchishandisa ImageJ software.Ukoshi hwedenderedzwa rakaenzana nechikamu chechikamu chakafanana neukoshi hunofananidzwa nehukuru hwemumiririri wechidimbu chimwe nechimwe chakayerwa.Mhedzisiro yemasampuli SFOA, SFOB uye SFOC inopfupikiswa muMufananidzo 3d-f, uye avhareji kukosha kwedhayamita inoshumwa zvakare.Kuwedzera tembiricha yekugadzirisa kunowedzera saizi yezvimedu uye hupamhi hwekugovera kwavo.Kubva pakuenzanisa pakati peVTEM neVXRD (Table Tafura 1), zvinogona kuonekwa kuti munyaya yeSFOA neSFOB samples, muvhareji wenhamba yemakristallite pachidimbu inoratidza chimiro chepolycrystalline yeaya lamellae.Kusiyana neizvi, iyo particle volume yeSFOC inofananidzwa neavhareji crystallite vhoriyamu, zvichiratidza kuti mazhinji emalamellae makristasi mamwe.Isu tinonongedza kuti saizi inooneka yeTEM uye X-ray diffraction akasiyana, nekuti mune yekupedzisira, isu tiri kuyera yakabatana yekuparadzira block (inogona kunge iri diki pane yakajairika flake): Uye zvakare, iyo diki kukanganisa kutaridzika kwekuparadzira uku. domains ichaverengerwa ne diffraction .
Iyo yakajeka-munda TEM mifananidzo ye (a) SFOA, (b) SFOB uye (c) SFOC inoratidza kuti inoumbwa nezvidimbu zvine chimiro chakafanana neplate.Iyo inoenderana saizi kugoverwa inoratidzwa muhistogram yepaneru (df).
Sezvatakaonawo muongororo yapfuura, makristallite ari muupfu chaiwo sampuli inoumba polydisperse system.Sezvo nzira ye-X-ray inonyanya kunzwisiswa kune yakabatana yekuparadzira bhuroka, kunyatsoongorora kweiyo poda diffraction data inodiwa kutsanangura yakanaka nanostructures.Pano, ukuru hwemakristallite hunokurukurwa kuburikidza nekufananidzwa kwevhoriyamu-inorema crystallite saizi yekugovera basa G (L) 23, iyo inogona kududzirwa seyakakwana density yekuwana makristallite ehunofungidzirwa chimiro uye saizi, uye huremu hwayo hunoenzana it.Vhoriyamu, mumuenzaniso wakaongororwa.Ne prismatic crystallite chimiro, avhareji yevhoriyamu-inorema crystallite saizi (avhareji yerutivi kureba mu [100], [110] uye [001] mirayiridzo) inogona kuverengerwa.Naizvozvo, takasarudza ese matatu maSFO samples ane akasiyana particle sizes muchimiro cheanisotropic flakes (ona Reference 6) kuti tiongorore kushanda kweiyo nzira kuti tiwane chaiyo crystallite saizi yekugovera nano-scale zvinhu.Kuti uongorore kutaridzika kweanisotropic ye ferrite crystallites, mutsara wekutsvaga mutsara wakaitwa pane data ye XRPD yezvikomo zvakasarudzwa.Iyo yakaedzwa SFO samples yakanga isina nyore (yakachena) yakakwirira kurongeka kusiyanisa kubva kune imwechete seti yekristaro ndege, saka zvaive zvisingaite kuparadzanisa mutsara wekuwedzera mupiro kubva pakukura uye kukanganisa.Panguva imwecheteyo, iyo yakacherechedzwa kuwedzera kwemitsara yekusiyanisa kunowanzo kuve nekuda kwehukuru hwekuita, uye avhareji yekristallite chimiro inosimbiswa kuburikidza nekuongororwa kwemitsara yakawanda.Mufananidzo 4 unoenzanisa vhoriyamu-inorema crystallite saizi yekugovera basa G (L) pamwe neyakatsanangurwa crystallographic nzira.Iyo yakajairika fomu yekugovera saizi yekristallite ndeye lognormal kugovera.Imwe hunhu hwese hwakawanikwa saizi kugoverwa ndeye unimodality yavo.Kazhinji, kugovera uku kunogona kuverengerwa kune imwe yakatsanangurwa particle maumbirwo maitiro.Musiyano uripo pakati peavhareji yakaverengerwa saizi yenhongonya yakasarudzwa uye kukosha kwakatorwa kubva kuRietveld kunatsiridza kuri mukati mechikamu chinogamuchirika (tichifunga kuti maitiro ekugadzirisa chiridzwa akasiyana pakati penzira idzi) uye yakafanana neiyo kubva kune inowirirana seti yendege ne Debye Ivhareji yehukuru yakawanikwa inopindirana neScherrer equation, sezvinoratidzwa muTebhu 2. Mamiriro ehuwandu hwehuwandu hwekristallite yehukuru hwemhando mbiri dzakasiyana-siyana dzakanyanya kufanana, uye kutsauka kwehukuru hwakakwana kuduku zvikuru.Kunyangwe panogona kunge paine kusawirirana naRietveld, semuenzaniso, kana iri (110) ratidziro yeSFOB, inogona kunge ine hukama nekutemerwa kwechokwadi kwemashure kumativi ese echiratidzo chakasarudzwa pachinhambwe che1 degree 2θ mune imwe neimwe. direction.Zvakadaro, chibvumirano chakanakisa pakati peaviri matekinoroji chinosimbisa kukosha kweiyo nzira.Kubva pakuongorora kwekuwedzera kwepamusoro, zviri pachena kuti ukuru pamwe chete [001] inotsamira panzira yekubatanidza, zvichikonzera kuumbwa kwemakristallite asina kujeka muSFO6,21 akagadzirwa nesol-gel.Ichi chimiro chinovhura nzira yekushandiswa kweiyi nzira kugadzira nanocrystals ine yakasarudzika maumbirwo.Sezvatinoziva tese, iyo yakaoma crystal chimiro cheSFO (sezvinoratidzwa muMufananidzo 1) ndiyo musimboti weiyo ferromagnetic maitiro eSFO12, saka chimiro uye saizi hunhu zvinogona kugadziridzwa kuti optimize dhizaini yesample yezvikumbiro (senge zvekusingaperi. magineti ane hukama).Isu tinonongedza kuti crystallite saizi yekuongorora inzira ine simba yekutsanangura iyo anisotropy yecrystallite maumbirwo, uye inosimbisa zvakare yakambowanikwa mhedzisiro.
(a) SFOA, (b) SFOB, (c) SFOC yakasarudzwa ratidziro (100), (110), (004) vhoriyamu inorema crystallite saizi kugovera G(L).
Kuti tiongorore kushanda kwemaitiro ekuwana iyo chaiyo crystallite saizi yekugovera nano-upfu zvinhu uye kuishandisa kune yakaoma nanostructures, sezvakaratidzwa muFigure 5, takaona kuti nzira iyi inoshanda mune nanocomposite zvinhu (nominal values).Kurongeka kwenyaya inoumbwa neSrFe12O19/CoFe2O4 40/60 w/w %).Migumisiro iyi inonyatsoenderana nekuongorora kweRietveld (ona chinyorwa cheMufananidzo 5 kuti uenzanise), uye zvichienzaniswa ne-single-phase system, SFO nanocrystals inogona kusimbisa imwe plate-like morphology.Mhedzisiro iyi inotarisirwa kushandisa iyi mutsara profil ongororo kune mamwe masisitimu akaomarara umo akati wandei akasiyana makristasi nhanho anogona kupindirana pasina kurasikirwa neruzivo pamusoro pezvimiro zvavo.
Iyo vhoriyamu-inorema crystallite saizi yekugovera G (L) yeakasarudzwa kuratidzira kweSFO ((100), (004)) uye CFO (111) mune nanocomposites;kuenzanisa, iyo inoenderana Rietveld yekuongorora kukosha ndeye 70 (7), 45 (6) uye 67 (5) nm6.
Sezvinoratidzwa muMufananidzo 2, kugadziriswa kwehukuru hwemagineti uye kuenzanisa kwakarurama kwehuwandu hwemuviri ndiyo nheyo yekutsanangura maitiro akaoma akadaro uye nekunzwisisa kwakajeka kwekubatana uye kurongeka kwemaitiro pakati pemagineti particles.Munguva pfupi yapfuura, maitiro emagineti eSFO samples akadzidzwa zvakadzama, nekutarisisa kudzoreredza maitiro emagnetization, kuitira kudzidza iyo isingachinjiki chikamu chemagnetic susceptibility (χirr) (Mufananidzo S3 muenzaniso weSFOC)6.Kuti tiwane kunzwisisa kwakadzama kweiyo magnetization reversal mechanism mune ino ferrite-based nanosystem, takaita chiyero chekuzorora magineti mundima yekumashure (HREV) mushure mekuzara mune imwe nzira.Funga \(M\kuruboshwe(t\kurudyi)\proptoSln\left(t\kurudyi)\) (ona Mufananidzo 6 uye zvekuwedzera kuti uwane rumwe ruzivo) wobva wawana iyo activation vhoriyamu (VACT).Sezvo ichigona kutsanangurwa sediki vhoriyamu yezvinyorwa zvinogona kudzoserwa zvakabatana muchiitiko, iyi parameter inomiririra "magnetic" vhoriyamu inobatanidzwa mukudzoreredza maitiro.Yedu VACT kukosha (ona Tafura S3) inoenderana nebhora rine dhayamita ingangoita makumi matatu nm, inotsanangurwa seyakabatana dhayamita (DCOH), iyo inotsanangura muganho wepamusoro weiyo system's magnetization reversal nekutenderera kwakabatana.Kunyangwe paine musiyano muhombe muhuwandu hwemuviri wezvimedu (SFOA yakakura zvakapetwa kagumi pane SFOC), hunhu uhu hunogara huripo uye hudiki, zvichiratidza kuti magineti ekudzoreredza masystem eese masisitimu anoramba akafanana (zvichienderana nezvatinoti. ndiyo imwechete domain system) 24 .Pakupedzisira, VACT ine vhoriyamu diki yemuviri kupfuura XRPD uye TEM kuongororwa (VXRD neVTEM muTafura S3).Nokudaro, tinogona kugumisa kuti kuchinja kwekushandura hakuitike chete kuburikidza nekutenderera kwakabatana.Ziva kuti mibairo yakawanikwa nekushandisa akasiyana magineti (Mufananidzo S4) inopa zvakafanana DCOH hunhu.Panyaya iyi, zvakakosha zvikuru kutsanangura dhayamita yakakosha yeimwe domain particle (DC) kuitira kuti uone nzira inonzwisisika yekudzokera shure.Zvinoenderana nekuongorora kwedu (ona zvinyorwa zvekuwedzera), tinogona kutaura kuti VACT yakawanikwa inosanganisira isina kutenderera nzira yekutenderera, nekuti iyo DC (~ 0.8 µm) iri kure kwazvo neDC (~ 0.8 µm) yezvimedu zvedu, kureva, kuumbwa kwemadziro emadziro hakuna Ipapo yakagashira rutsigiro rwakasimba uye yakawana imwechete domain configuration.Ichi chigumisiro chinogona kutsanangurwa nekuumbwa kwekubatana domain25, 26. Isu tinofungidzira kuti imwe chete crystallite inobatanidzwa mune imwe nzvimbo yekubatana, iyo inowedzera kune zvikamu zvakabatana nekuda kwehterogeneous microstructure yezvinhu izvi27,28.Kunyange zvazvo nzira dze-X-ray dzinongonzwa kune yakanaka microstructure ye domains (microcrystals), zviyero zvekuzorodza magineti zvinopa humbowo hwezviitiko zvakaoma zvinogona kuitika mune nanostructured SFOs.Naizvozvo, nekugadzirisa saizi ye nanometer yeSFO zviyo, zvinokwanisika kudzivirira kuchinjika kune yakawanda-domain inversion process, nekudaro kuchengetedza kumanikidza kwakanyanya kwezvinhu izvi.
(a) Iyo nguva-inotsamira magineti curve yeSFOC yakayerwa payakasiyana reverse ndima HREV kukosha mushure mekuzara pa-5 T uye 300 K (inoratidzwa padivi peyekuyedza data) (magnetization inojairwa zvichienderana nehuremu hwesample);kujekesa, Iyo inset inoratidza data yekuyedza ye0.65 T munda (dema denderedzwa), iyo ine yakanyanya kukwana (mutsara mutsvuku) (magnetization inojairika kune yekutanga kukosha M0 = M (t0));(b) iyo inoenderana nemagnetic viscosity (S) ndiyo inverse yeSFOC Basa remunda (mutsara igwara reziso);(c) activation mechanism scheme ine yemuviri / magineti kureba chiyero.
Kazhinji kutaura, magnetization reversal inogona kuitika kuburikidza nenhevedzano yemaitiro emunharaunda, senge domain madziro nucleation, kuparadzira, uye pinning uye unpinning.Panyaya ye single-domain ferrite particles, iyo activation mechanism ndeye nucleation-mediated uye inokonzereswa nekuchinja kwemagnetization kudiki pane iyo yakazara magineti reversal volume (sezvinoratidzwa mumufananidzo 6c) 29.
Mukaha uripo pakati peiyo yakakosha magineti uye dhayamita yemuviri inoreva kuti iyo incoherent modhi chiitiko chinopindirana chemagnetic domain reversal, inogona kunge iri nekuda kwezvinhu inhomogeneities uye kusaenzana kwepasi, izvo zvinove zvakabatana kana saizi yechikamu ichiwedzera makumi maviri neshanu, zvichikonzera kutsauka kubva. yunifomu magnetization mamiriro.
Naizvozvo, tinogona kugumisa kuti muhurongwa uhu, iyo magnetization reversal process yakaoma kwazvo, uye kuedza kuderedza saizi muyero ye nanometer kunoita basa rakakosha mukudyidzana pakati peiyo microstructure yeferrite uye magineti..
Kunzwisisa hukama hwakaoma pakati pechimiro, fomu uye magineti ndiyo hwaro hwekugadzira nekugadzira ramangwana maapplication.Kuongororwa kwemutsara weiyo yakasarudzwa XRPD pateni yeSrFe12O19 yakasimbisa anisotropic chimiro chenanocrystals yakawanikwa nenzira yedu yekubatanidza.Yakasanganiswa neTEM kuongororwa, iyo polycrystalline chimiro chechikamu ichi chakaratidzwa, uye chakazosimbiswa kuti ukuru hweSFO yakaongororwa mubasa iri yakanga yakaderera pane yakakosha domain domain diameter, pasinei neuchapupu hwekukura kwekristallite.Pahwaro uhwu, isu tinokurudzira isingadzokerike magineti maitiro zvichienderana nekuumbwa kwenzvimbo yekudyidzana inoumbwa neakabatana crystallites.Mhedzisiro yedu inoratidza hukama hwepedyo pakati peiyo particle morphology, chimiro chekristaro uye saizi yekristallite iripo padanho renanometer.Ichi chidzidzo chine chinangwa chekujekesa iyo inodzosera magineti maitiro ezvakaoma nanostructured magineti uye kuona basa reiyo microstructure maitiro mune inokonzeresa magineti maitiro.
Mienzaniso yacho yakashandiswa uchishandisa citric acid sechelating agent / mafuta maererano ne-sol-gel spontaneous combustion nzira, yakashumwa muReference 6. Mamiriro ekugadzirisa akagadziridzwa kuti awane matatu akasiyana-siyana emasampuli (SFOA, SFOB, SFOC), ayo akanga yakawanikwa nekurapa kwakakodzera kweannealing patembiricha dzakasiyana (1000, 900, uye 800 ° C, zvichiteerana).Tafura S1 inopfupikisa iyo magineti zvivakwa uye inoona kuti dzakada kufanana.Iyo nanocomposite SrFe12O19/CoFe2O4 40/60 w/w% yakagadzirirwawo nenzira yakafanana.
The diffraction pattern yakayerwa pachishandiswa CuKα mwaranzi (λ = 1.5418 Å) paBruker D8 powder diffractometer, uye detector slit width yakaiswa ku 0.2 mm.Shandisa VANTEC counter kuunganidza data mu 2θ renji ye10-140 °.Tembiricha panguva yekurekodha data yakachengetedzwa pa23 ± 1 °C.Iyo ratidziro inoyerwa nedanho-uye-scan tekinoroji, uye nhanho kureba kweyese bvunzo samples ndeye 0.013 ° (2theta);huwandu hwepamusoro hwepamusoro hwechiyero chekuyera -2.5 uye + 2.5 ° (2theta).Panhongonya yega yega, huwandu hwe106 quanta hunoverengerwa, nepo kumuswe kune 3000 quanta.Nhamba dzinoverengeka dzekuyedza (dzakapatsanurwa kana kupindirana zvishoma) dzakasarudzwa kuti dziwedzere kuongororwa panguva imwe chete: (100), (110) uye (004), iyo yakaitika paBragg angle padyo neBragg angle yeSFO mutsara wekunyoresa.Kusimba kwekuyedza kwakagadziriswa kweiyo Lorentz polarization factor, uye kumashure kwakabviswa nekufungidzirwa shanduko yemutsara.Iyo NIST yakajairwa LaB6 (NIST 660b) yakashandiswa kukwenenzvera chiridzwa uye kukudza chitarisiko.Shandisa LWL (Louer-Weigel-Louboutin) deconvolution nzira 30,31 kuti uwane mitsetse yakachena ye diffraction.Iyi nzira inoshandiswa muchirongwa chekuongorora purogiramu PROFIT-software32.Kubva pakukodzera kweyakayerwa intensity data yemuenzaniso uye chiyero chine pseudo Voigt basa, mutsara unoenderana nawo contour f(x) inotorwa.Saizi yekugovera basa G(L) inotarwa kubva paf(x) nekutevera maitiro anoratidzwa muReference 23. Kuti uwane rumwe ruzivo, ndapota tarisa kune yekuwedzera.Sekuwedzera kune mutsara wekuongorora mutsara, chirongwa cheFULLPROF chinoshandiswa kuita Rietveld kuongorora pane data yeXRPD (mashoko anogona kuwanikwa muMaltoni et al. 6).Muchidimbu, mumuenzaniso weRietveld, mapeaks ekusiyana anotsanangurwa neakagadziridzwa Thompson-Cox-Hastings pseudo Voigt basa.Kukwenenzverwa kweLeBail kweiyo data kwakaitwa paNIST LaB6 660b chiyero kuratidza mupiro wechiridzwa pakuwedzera kwepamusoro.Zvinoenderana neyakaverengerwa FWHM (yakazara hupamhi pahafu yepamusoro-soro), iyo Debye-Scherrer equation inogona kushandiswa kuverenga vhoriyamu-yakayerwa avhareji saizi yeyakabatana yekuparadzira crystalline domain:
Apo λ ndiyo X-ray radiation wavelength, K ndiyo chimiro chechimiro (0.8-1.2, kazhinji yakaenzana ne0.9), uye θ ndiyo Bragg angle.Izvi zvinoshanda kune: kuratidzwa kwakasarudzwa, iyo inopindirana seti yendege uye iyo yose muenzaniso (10-90 °).
Pamusoro pezvo, Philips CM200 microscope inoshanda pa200 kV uye yakashongedzerwa neLaB6 filament yakashandiswa kuongororwa kweTEM kuwana ruzivo nezve particle morphology uye saizi kugovera.
Magnetization yekuyeresa kuyerwa kunoitwa nezviridzwa zviviri zvakasiyana: Physical Property Measurement System (PPMS) kubva kuQuantum Dhizaini-Vibrating Sample Magnetometer (VSM), ine 9 T superconducting magineti, uye MicroSense Model 10 VSM ine electromagnet.Munda uri 2 T, sampuli yakazara mumunda (μ0HMAX: -5 T uye 2 T, zvakateerana kune imwe neimwe chiridzwa), uye ipapo iyo reverse ndima (HREV) inoshandiswa kuunza sample munzvimbo yekuchinjisa (pedyo neHC. ), uye ipapo Kuora kwemagnetization kunonyorwa senge basa renguva pamusoro pe60 maminetsi.Kuyera kunoitwa pa300 K. Iyo inoenderana activation vhoriyamu inoongororwa zvichienderana neaya akayerwa kukosha anotsanangurwa mune yekuwedzera zvinhu.
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